‘Health Chatter’: The Health Behaviour Research Centre Blog

As mentioned in one of our previous blog posts, talking about genes in the context of obesity is often not well received.  Those discounting their role in the development of obesity often argue that, because genes have not substantially changed over the past 200 000 years, whereas obesity levels have only been soaring over the past 20 odd years (where it became possible to mass-produce cheap, tasty food in combination with a decreased need for physical activity), obesity must be due to changes in the environment, and not genetics.

However, using this argument against the heritability of obesity is somewhat flawed, because it ignores that a condition can be dormant over a period of time until the right circumstances bring it to life.  The gardeners among you will know that many plants will adjust their growth according to their surroundings – a plant in a small pot will remain small, whereas a larger pot will allow it to grow.   This, however, does not mean that the plant loses its ability to grow larger in a smaller pot; it merely remains small because its surroundings restrict its growth.  Similarly, genes predisposing to obesity may be present in an environment where little food is available, but without the right ‘medium’ (i.e. food), this is of little consequence.  In the current environment, however, where eating opportunities are plentiful, obesity genes can express their full force.

If obesity was resulting purely from environmental change, all individuals exposed to this change would become overweight.  Yet, this is not the case. In fact, the proportion of lean people has not substantially changed, but large people are becoming even larger.  This suggests that people respond to the food environment differently.  However, undoubtedly, to gain more weight than is healthy, food must not only be available in sufficient quantities, but one must ingest more of it than necessary.  Therefore, researchers started to look at differences in eating behaviours, such as how much we are drawn to food and how quickly we feel full, to see what is going on.

Twins can help to untangle the influence of genes and environment on obesity, because identical twins are 100% genetically identical, whereas non-identical twins only share approximately half of their genes (like normal siblings); both, however, grow up in a very similar environment.  This means that researchers can compare identical twins’ resemblance for weight with that of non-identical twins; if genetically identical twins are more similar in a trait than non-identical twins, it is evidence for genes being responsible for the trait.

Using twins, researchers from our department wanted to see whether genes that influence weight also influence appetite.  If the same genes that influence weight also influence appetite, it suggests that genes influence weight through their effects on appetite – i.e. individuals who inherit more avid appetites might be more susceptible to overeating in the modern food environment, and consequently  more likely to gain excessive weight.  They looked at this in infants, because infants are exclusively milk-fed, which ruled out that other factors such as preference for certain foods would influence the results.   The researchers used questionnaires to ask parents about how fast their twins fed, how easily they got full and how big their appetite was, and related the answers to the babies’ weight.   Because they used a sample of identical and non-identical twins the researchers were able to explore the extent to which appetite is heritable, and the extent to which appetite and weight are caused by the same genes.

They found that identical twins were not only very similar in weight, but shared many more similarities in appetite than non-identical twins, suggesting a strong genetic basis to both appetite and weight.  In addition, the results  showed that a substantial proportion of the genes that are responsible for weight are also responsible for appetite, in line with the idea that genes influence weight through appetite.  These findings lend evidence to the idea that some of us are more likely to overeat in the current environment because of a larger appetite, which is ultimately driven by genes.

These discoveries will hopefully contribute to reducing the stigma that surrounds unhealthy weight gain; because it clearly shows that those struggling with weight are in a sense ‘battling against their biology’.  This of course, does not mean that there is nothing that can be done about it; however, acknowledging these differences as real and designing strategies to ‘outsmart’ one’s genes is crucial if the battle is to be fought successfully.

Article reference: http://www.ajcn.org/content/95/3/633.long

You don’t need to be Jamie Oliver to figure out what is going on with children’s diets – but his efforts certainly helped to pull the candyfloss from our eyes:  children in England are eating plenty of snacks high in fat, salt and sugar, but only one quarter eats their recommended minimum 5 portions of fruit and vegetables a day.  This can be problematic, because not only could it lead to nutritional deficiencies, but also to disproportionate weight gain.

Unfortunately, it is not the case that children simply ‘outgrow’ their ‘puppy-fat’; the vast majority of overweight children grow into overweight teenagers and potentially obese adults.  This is because people naturally put on about 2 pounds per year as they age (unless they do something about it, of course) – and the higher the ‘starting weight’ is, the higher the chances are that people shift up across the weight spectrum as they get older. Furthermore, people who become overweight or obese early in life are often more severely affected by illnesses linked with an unhealthy weight, such as diabetes, heart disease and some cancers.

This is why it is important to figure out what it is that makes children eat their greens (and all those other healthy fruit and veggies, even if cooking like Jamie isn’t your thing).  It has long been known that many different factors such as inherited taste preferences, family eating habits or the amount of time spent watching TV are important when looking at reasons why children eat (or don’t eat) certain foods; but rarely has research looked at factors related to healthy and unhealthy eating habits at the same time in the same group of families.

In this study, the researchers were interested in the actual foods children in England eat (as opposed to specific nutrients, such as vitamins). The researchers had records of what children and their parents ate from several hundred families, along with information on factors which may influence what they eat.  They decided to look in particular at factors which affected how much fruit, vegetables, unhealthy snacks and sugary drinks children consume; focusing on preschool-aged children – as they are not yet strongly influenced by their peers, and are more dependent on eating what their caregivers provide for them.

Perhaps unsurprisingly, the researchers found that when children liked the taste of fruit and veggies it predicted how much of these they ate.  However, what is more important, they also found that parents’ consumption of either fruit, vegetables, unhealthy snacks or sweetened drinks was a very important indicator of how much children ate of these foods.  This might be not only because caregivers may feed children what they themselves eat, but also because children tend to copy adults’ behaviour – so if mum eats healthily, children will be more likely to want to eat healthily too.  Of course, that is also true for unhealthy eating habits – which is why not having junk foods in the home in the first instance can help.  Because it was mainly mothers who filled out the questionnaires, these results focused only on mothers.

Furthermore, praising children for eating fruit and veggies was a good indicator of how much children ate, and monitoring the unhealthy snacks children eat was linked with them eating less of these and more fruit and vegetables.  The amount of time children spent watching TV was also an indicator of children eating unhealthy snacks and having sweetened drinks, but it had no impact on their consumption of fruit and vegetables.

The research provides a little more evidence on how eating habits are transmitted within a family.  It highlights that different strategies need to be used in order to increase the amount of healthy foods vs. decreasing amounts of unhealthy foods children eat.

So, ultimately, if you want your children to eat their greens, you might not have any choice but to take a bite too and start singing their praises, and if you really want to cut down on their junk intake then get rid of it from within your home and turn off the telly – and at last Jamie will be happy.

http://www.nature.com/ejcn/journal/vaop/ncurrent/full/ejcn2011224a.html

If you thought that the stresses of present-picking, turkey-basting and relative-juggling are to blame for weight gain, you are not alone. A Google search for ‘stress and weight gain’ reveals a staggering 32,000,000 sites dealing with the topic. However, researchers from our research group have shown that the effect of stress on weight gain may not be as large as you may have thought.

The body tries to maintain stability by adapting to a change in the environment, a process called homeostasis. Stress can be defined as any external factor, physical or psychological, which threatens to throw the body out of homeostasis. Whether running from a hungry lion, or suffering stage-fright before a speech, the body’s response will be the same: the stressor (lion or stage-fright) will trigger the so called ‘fight-or-flight-response’, which is marked by increased heartbeat, muscle-tension, sweating, dilation of the pupils and the release of the ‘stress-hormones’ adrenalin and cortisol. This response is extremely useful to mobilise resources, help us get through difficult situations and regain homeostasis. However, when we experience the on-going stresses of modern life, such as money-worries, job stress, or social pressures, we begin to feel the strain. Long-term stressors overwhelm the body’s coping system, deplete resources and ultimately lead to exhaustion. It has been thought that weight gain results from the body trying to restore homeostasis by inducing metabolic changes which promote fat storage on the one hand and behaviour changes on the other, for example making less time to be active or reaching for cookies instead of carrots.

Results from studies investigating this topic are mixed – some have found that stress has an effect on weight gain, and others have not. Researchers from our department decided to look at the effect from all these studies overall. Summarizing results of several studies on the same topic to find out the ‘true’ effect is called meta-analysis. The studies that were included in this meta-analysis had to be conducted over a period of time (because these are more accurate than studies that only look at a single time-point), measure weight objectively, and focus on external stressors such as life events, work-or caregiver stress. Fourteen studies from Europe and the USA met the criteria; each ‘stress category’ (life events, work- or caregiver stress) was analysed separately.

Results of the meta-analysis showed that stress is related to weight gain, although the effects were very small. When the researchers looked at the results in more depth, they saw that studies that went on for longer and were of better quality were more likely to show an effect of stress on weight. They also saw that the effect appeared to be stronger in men. It did not matter whether the stressor was related to life or work. Unfortunately, eating behaviour was not assessed, so the researchers could not tell whether it changed under stress.

Although there are not very many studies that looked at the topic over a period of time, and imprecise measurements of stress were often used, the findings are relatively robust because of the way the studies were combined. Finding a stronger link of stress on weight in men complements other findings which show that men have a stronger fight-or-flight response. Overall, however, it can be seen that the effects of stress on weight are much smaller than often made out in the media. Blaming the relatives for a bulging belly might be convenient, but complex issues like weight gain unfortunately have no simple, or convenient, answer.

Source: http://www.nature.com/oby/journal/v19/n4/full/oby2010241a.html

There it sits, on the counter, the vial which holds the key to knowledge, everything from ancestral lineage over earwax texture to my memory capacity. My strengths and weaknesses, the key to who I am…at least in genetic terms.

Proponents for direct to consumer genetic testing claim that a bit of spit contains everything I could possibly want to know about myself. The skeptics call it a genetic horoscope, as most results are no more accurate than traits attributed to star signs.

In recent years, companies emerged which offer genetic testing over the internet and promise to tell you more about your health and ancestry than you ever imagined.  With a couple of mouse clicks you can order one of their test kits, spit into a collection tube, seal it, send it back and within a few weeks you receive an email containing the link to a website which reveals your risk for a myriad of traits and diseases, half of which I would have trouble spelling, let alone pronounce.

Of course, doing a PhD in the subject calls for some self-experimentation, so my supervisor thought it would be a good idea for me to experience what this feels like … and this is how I ended up with a plastic tube full of spit.

It took me 3 days to send it off (apologies to the poor person in the lab who has to open that stinky tube). Why did it take me so long, I wonder? I consider myself as a curious individual interested in the latest scientific discovery, open to adopt new technologies…so why the hesitation?

I guess, because it felt like it could bring something to light which I might have happily left lurking in the dark. The 23andMe test I took reveals my risk for over 100 health conditions, some of which are quite severe, such as my risk for Huntington’s disease, Alzheimer’s or breast cancer. In addition, it shows my carrier status for various genetic diseases; my reaction to certain medications and finally personal traits such as memory capacity or the likelihood of ending up as an alcoholic. That, dear readers, is a lot of information. All at once, on one page.

Do I even want to know all of this? Even if I know that no cure exists for most of the diseases listed? The answer is: sort of. But, at this stage, only very few gene results can give meaningful risk estimations; most give only a minute indication of any change in risk – be it for better or for worse. The problem is also that conditions with exclusively genetic cause, such as Huntington’s Chorea, are listed with conditions where the picture is more complicated (for example in obesity).  This makes it very hard to know how much meaning to attach to a single risk result. I know I would be better off taking a long and hard look at my family history, if I wanted to get an idea of which diseases may be befalling me one day.

Nonetheless, I was incredibly curious to find out, and although my rational brain immediately told me that the results didn’t mean anything in the grander scope of things, they were all but unimportant. I felt something, and I definitely focused much more on the conditions where I was at a ‘higher risk’ than on those where I was classified as ‘average’ or ‘reduced risk’, regardless of what the actual risk estimation was.

The companies which provide direct to consumer genetic testing take quite a risk: They are providing medical results with minimal advice for conditions that many people may never have heard of, with risk estimations that don’t mean much objectively, but nonetheless seem to have an emotional impact – there is a lot of room for misunderstanding here.

For example, if I found out that my genetic risk of lung cancer is 6.8 % instead of the average of 6.2 %, then objectively that tells me that there is a whole host of factors other than my genes that play a role – however, because it is my personal  risk, it has some emotional meaning and in response

1. I could do the wise thing and stop smoking- advocates of these tests hope that we are using the information that we received to change our behaviour and prevent eventual illness

2. I could panic and ring my doctor for immediate 3 monthly check-ups – opponents of direct-to-consumer genetic testing fear that it might lead to unnecessary medical procedures

3. I could think that I will get lung cancer anyway and smoke even more, because of it – another concern of those cautioning against direct-to-consumer genetic testing

What will I do? What will other people do? I wouldn’t have been able to say before I took the test, because there is very little research on the subject to date. Now I know I will definitely not worry. But someone else might. It is an utterly individual experience, and there is certainly a good portion of narcissism attached.

Will I change anything? At the moment I am doing quite a lot of the ‘right’ things anyway, like being fairly active and eating sensibly (let’s keep quiet about the drinking) – but I’d like to think that it will have an impact when I am older. I think that it can be a positive influence on one’s health, because it raises awareness of potential illness and may be a motivation to look after oneself. Would I recommend it? Yes, but only if one is aware of the shortcomings of these tests, and if there is good information available about what the result means.

Despite all its criticisms, receiving those genetic results was a very unique experience, and I found out some things I am quite glad about. My eyes really are blue.  One thing, however, I didn’t look at: my genetic risk for Alzheimer’s disease. I think it would have been too disturbing to find out that I am more likely to get a severe illness for which there currently is no cure. But that was my individual choice. And that is what personalized genetic testing is all about.

Would you get tested? Why? Why not? Let me know below or send an email to Susanne.meisel.09@ucl.ac.uk

Promoting dieting for weight loss and weight maintenance is often criticized, because of the widely held belief that restricting food intake is the beginning of a slippery slope, leading to overeating and eating disorders.  However, a recent review by our department investigating the literature of dietary restraint shows that this may not be the case.

The idea that restricting food intake would lead to uncontrolled binge eating stems from laboratory studies from the 1970s.  Counter to expectations, people reporting that they were trying to lose weight by eating less (restrained eaters), ate more than unrestrained eaters when offered unhealthy but tasty food after being encouraged to break their diet by drinking a high calorie milkshake.  They also ate more than others after drinking alcohol or when they were upset.  These observations led to the belief that trying to control eating with one’s intellect rather than instinct can lead to less sensitivity to feelings of hunger and fullness, and cause people to overeat when their guard was lowered.  At the same time, research pinpointed dieting as a precursor of eating disorders, such as anorexia nervosa and bulimia nervosa, which further strengthened the lobby against the restriction of food intake.

However, closer examination of the research showed that the methods used to classify people as ‘restrained’ or ‘unrestrained’ eaters may have contributed to the findings.  For example, some of the questions asked to find out whether people restrict their food intake were actually assessing tendencies to eat in an uncontrolled way.  The links between restrictive eating and binge-eating were even less clear when considering the artificial lab setting in which participants were persuaded to break their diet, and then presented with an overwhelming amount of tasty food and told to eat as much as they wanted.

Furthermore, in the current environment, it may well be that a person eats less than desired, but still eats more than would be needed to keep weight stable.  Eating only one chocolate cake is better than eating two, but still, it can hardly be considered beneficial to your health!  This means that measuring food restriction alone may not be such a good indicator of successful weight management.  People who report restricting how much they eat may simply be the ones most likely to overeat.

Support for the positive effects of food restriction comes from real world examples.  In overweight individuals, where overeating is common, restricting food intake is related to lower body weight.  Findings from weight loss studies also show that the people doing best are the ones who vigilantly pay attention to what and how much they eat and don’t binge eat. In fact, evidence from studies with people suffering from binge eating has shown that gaining control over the amount of food eaten is related to fewer binge episodes.

So, how come the myth about the relationship between food restriction and disordered eating behaviour persists? The devil here may be in the detail of how people restrict their food intake. People who are following rigid, rule-based, ‘all-or-nothing’ eating are more likely to react with overeating and disordered eating once their rules are broken than people who take a more flexible approach, limiting rather than totally eliminating certain foods, and compensating for ‘off’ meals at the next meal or with an extra hour at the gym. Identifying oneself as a ‘dieter’ seems to be related to more rigid rules about eating and so may be undermining weight loss efforts.

The key to successful weight management may lie not in restraint per se, but in self-control. The ability to forego immediate rewards in pursuit of higher goals seems to be a skill that, once acquired, is not limited to successful weight management, but extends to other areas of life such as success at work, and better management of time and finances.  Although the capacity to control one’s desires seems to be partly inherited, the good news is that people can also be trained in self-control.  Learning how to control emotions, monitoring and evaluating one’s own  behaviour, setting goals, acquiring more beneficial problem-solving skills and thinking up action plans for resisting temptations have all been shown to enhance self-control.  The view that restraint is always ‘bad’ may need to be revised and the distinction between ‘rigid’ and ‘flexible’ restraint should be given more consideration.

The bottom line is that exercising a little restraint may not only benefit your weight but also your wallet, as long as it does not turn you into a rigid, miserly and overly concerned kill-joy.

Article Reference: Johnson, F., Pratt, M., Wardle, J. (2011). Dietary restraint and self-regulation in eating behavior. Int J Obes (Lond) doi:10.1038/ijo.2011.156.

The falling cervical screening rates in younger women could be explained by their hectic lifestyles

It is a familiar story, every day you add a few more things on your to-do list, book a haircut; pay that cheque in; send a birthday card to your best friend.  In theory you should tick them off in order, first on first done or even better prioritise, ticking off the most important jobs first.  In reality the list grows and grows and although you tick off a few jobs each week (if you don’t post that birthday card before you friend’s birthday, it won’t be worth posting it), there are a handful of old-timers that remain week after week, month after month.  And going for a smear test might be one of these.

In our first blog we talked about how our research suggests the more some people think about the nitty gritty of doing a screening test, the less appealing it is to them.  Another reason for not doing screening could be that it simply drops to the bottom of your list, because life gets in the way.  Our recent study suggests that this could be one reason why fewer young women are going for cervical screening in England.  Since 1999, there’s been a drop of 12% in attendance for smear tests in 25-29 year olds, and we’ve been trying to understand why.

We interviewed and ran focus groups with 46 women who weren’t up to date with their smear tests, making sure we included young and older women so we could compare them.  The women discussed their reasons for not going for screening.  There seemed to be two distinct patterns of non-attendance.  Some of the women described how they had actively decided not to be screened.  These women either felt they were not at risk of cervical cancer or had weighed up the risks and benefits of screening and decided not to attend.  The second group of women described how although they intended to go for screening, they did not get round to it.  A variety of reasons were given, such as finding it difficult to make appointments to fit in with work commitments or childcare arrangements and feeling that cervical screening was at the bottom of their list: “I’ve got to have blood tests, I’ve got to go to the dentist, I’ve got to get my hair cut, so what’s low in priority, and a cervical smear test would be right down there I think”.  Interestingly, it seemed to be the older women who were making informed decisions not to attend, while the younger women just didn’t get round to going.

The findings complement a survey study that we published in 2009.  The study included a population-based sample of 580 women aged 26-64 years.  Women answered questions about their cervical screening uptake and selected which statements they agreed with from a list of possible barriers to attending screening.  While the most common barrier was embarrassment, this was chosen equally by women who did and did not attend screening regularly.  The second most common barrier was: “I intend to go… but don’t always get round to it”. This barrier was chosen more by women in the younger age group (26-34 years: 25%) than the older age group (55-64 years: 8%) and alongside “it is difficult to get an appointment” and “I do not trust the smear test” was associated with being overdue for screening.

Our findings have some interesting implications for how cancer screening is offered to younger women.  Using prompts (e.g. advertisements or text reminders) could be a useful way of overcoming the gap between intention and behaviour, reminding women that ‘Go for a smear’ is still on their to-do list.  Making screening more convenient (e.g. available at locations near work places or offering extended clinic hours) could also make it easier for women to fit in going for a smear test.  It can then be marked job done.

References:

Waller J, Jackowska M, Marlow L, Wardle J. Exploring age differences in reasons for non-attendance for cervical screening: a qualitative study. BJOG, in press. DOI: 10.1111/j.1471-0528.2011.03030.x

Waller J, Bartoszek M, Marlow L, Wardle J. (2009) Barriers to cervical cancer screening attendance in England: a population-based survey. Journal of Medical Screening, 16:199-204. DOI: 10.1258/jms.2009.009073

Laura (l.marlow@ucl.ac.uk)

Cancer fatalism may be the driving mechanism linking social background with negative views on the early detection of cancer

One of the great success stories of modern medicine is that more and more people are surviving cancer these days. Whether this is due to better treatment options, improved ways of detecting it, or indeed novel ways to stop it from happening in the first place, may be a matter of debate.  However, we can say with some certainty that the triumphs in the battle against cancer are rarely due to the big ‘breakthroughs’ that are reported regularly in the press.  Instead, achievements arise from gradual improvements in all aspects of cancer research, which go hand in hand with slow, but steady increases in survival rates. Of interest to cancer communication specialists is whether public impressions of the disease move in line with these improvements? Or does the impression remain that cancer is a deadly unsurvivable monster that we are powerless to control and should not be discussed in polite conversation?

In order to investigate the issue further, behavioural scientists have begun to investigate the construct of ‘fatalism’ – the perception that an event is uncontrollable and the outcome is a foregone conclusion. Previous research has shown that people holding fatalistic beliefs about cancer are less likely to engage in behaviours that would help to ward off cancer, such as screening, self-examination and accessing health information. This is particularly true among people from deprived backgrounds, which tend to have more negative attitudes towards early detection of cancer, possibly because they are more likely to encounter negative life (and health) events than people who are less deprived. (See figure 1 for summary).

The latest publication from the HBRC aimed to combine these findings by investigating the relationship between social background, fatalism and views on early cancer detection outlined in figure 1. In the study a large sample, which accurately reflected the UK population was used. The question the researchers tried to answer was whether the relationship between social deprivation and negative views on early detection could be explained by the disadvantaged group’s tendency to hold more fatalistic beliefs towards cancer.

Cancer fatalism was measured in two ways. In one question participants had to estimate how many people with a cancer diagnosis would be alive 5 years later. Their answers were then compared with actual survival figures, with people being classified as ‘accurate’ if they answered 41-50% or 51-60%, ‘pessimistic’ if they answered 0-40% and ‘optimistic’ if they answered >60%. In the second question participants were asked their agreement with the statement ‘Many people who get cancer can be completely cured’ on a graded rating scale.

The results showed that the public’s impression of cancer survival is generally accurate; with most people correctly selecting that 51-60% of people will survive for at least 5 years following a cancer diagnosis. Individuals from the most deprived group were more likely to be classified as ‘pessimistic’, less likely to be classified as ‘optimistic’ and tended to answer towards the ‘strongly disagree’ end of the scale for the second measure of fatalism. In sum, this is evidence for fatalistic attitudes being stronger in deprived groups.

Next, Dr. Rebecca Beeken and colleagues from the HBRC showed that over 90% of their sample agreed with the statement ‘the earlier cancer is detected, the greater the chance of successful treatment.’ This is great news and shows that the message of early detection is getting through to the public. Unfortunately, individuals from socially deprived groups were more likely to disagree with this statement, suggesting more work is needed in promoting this message among this group.

However, the question is whether this relationship is explained by a greater tendency to hold fatalistic beliefs? In short, the answer is yes. After examining all of these constructs (and a couple of others that might influence the relationship) in a statistical model, it was shown that after considering fatalistic beliefs, the relationship between social deprivation and negative attitudes towards early detection disappeared. In other words, it is fatalistic beliefs which drive negative attitudes towards cancer detection and not simply being part of a socially deprived group.

The finding that the U.K public generally has an accurate impression of cancer survival rates and that the message of early detection is starting to get through is great news for health promotion and behavioural scientists in the field of cancer communication. Although deprived groups tend to have more negative attitudes towards early detection, we now know that cancer fatalism is a strong mechanism that drives these beliefs. This gives us something to target when we are delivering the early detection message.

As cancer scientists in all fields continue to develop better cures and treatments for the disease, it is important that the public keep up to date with the progress we are making. Although it appears from the current research that we are doing a good job, we must not rest on our laurels. Only when the differing attitudes towards cancer between social groups begin to converge can we be sure that everyone is equally sharing the amazing developments that are happening in the world of cancer.

Reference: Beeken RJ, Simon AE, von Wagner C, Whitaker KL, Wardle J (in press) Cancer fatalism: deterring early presentation and increasing social inequalities? Cancer Epidemiology, Biomarkers & Prevention. DOI: 10.1158/1055-9965.EPI-11-0437

Sam (Samuel.smith@ucl.ac.uk)

Mentioning genetics in the context of weight is like treading into a minefield; those who are brave enough to approach the topic need to don their hard hats and be prepared to take hits by followers in the ‘eat-less-and-move-more’ camp. Accusations of laziness, lack of willpower, making excuses and just looking for an easy way out are common responses to the genetic argument of obesity.

However, to ignore genetics when talking about obesity is somewhat confusing when considering how keen people are to attribute skinniness to ‘good genes’, ‘fast metabolism’, and ‘being naturally active’. Nobody seems to notice that skinniness and fatness are two sides of the same coin.

As so often in life, the truth lies somewhere in between. While behaviour is certainly not to be ignored when searching for the root cause of the obesity epidemic, neither should the heritability of body weight. Two recent studies from our research group add evidence to the idea that the predisposition to thinness, as well as to overweight, is transmitted across generations. Researchers used data from the Health Survey for England, which included a large sample of families with children aged 2-15 years to see whether thin children were more likely to have thin parents. Of the thousands of families included in the first study, it was shown that thin children were almost twice as likely to have 2 thin parents.  Furthermore, as parents’ weight decreased, children likewise got progressively lighter.

But, what about the reverse side of the coin – parental weight of children who were overweight? Here, exactly the same pattern was found, but it was even more apparent. Children, who had 2 obese or severely obese parents, were approximately 12 times more likely to be overweight and again the likelihood of obesity gradually decreased with decreased parental body weight. In both studies, findings were unrelated to other factors such as age, sex, social status or ethnicity. Interestingly, the mothers’ weight seemed to be more predictive of a child’s than the father’s, but only among those children that were overweight. For thin children, mothers’ and fathers’ genes appeared to contribute equally to being thin.

Two things are important here. Firstly, weight is governed in part by genetic factors; but, and this is the second important conclusion to take away, there are environmental factors involved that influence a child’s weight – otherwise all children would have had parents that fully resembled their weight status. Influences seem to come especially from the mother’s side, which may be, because the foetus receives nutrients from the maternal diet in the womb and after birth when the infant is breast-fed. In addition, maternal environmental influences may be stronger because the mother is usually in charge of food preparation.

Unfortunately, dietary records of participants were not available, so it was not possible to investigate how diets between underweight and overweight children and their parents differed.

Genes do not always act in the same way; their activity is influenced by the environment. This flexibility allowed our species to adapt well to changing environmental conditions, which made it possible to survive and evolve.  Variation is the key. And this is why it is easier for some than for others to (not) have their cake and eat it, too.

References:

Whitaker KL, Jarvis MJ, Boniface D, Wardle J. Inter-generational transmission of thinness. Archives of Pediatrics and Adolescent Medicine. http://archpedi.ama-assn.org/cgi/content/full/165/10/900

Whitaker KL, Jarvis, MJ, Beeken RJ, Boniface D, Wardle J. Comparing maternal and paternal intergenerational transmission of obesity risk in a large population-based sample. American Journal of Clinical Nutrition. 91, 2010, 1560-1567. http://asn-cdn-remembers.s3.amazonaws.com/f8ee4cfad55bd34900cff3371b9a146d.pdf

How self-monitoring tools and participation in online support groups assists weight loss

The internet can be a wonderful place, with hours of fun to be had looking at unlimited amounts trivial information, bad adverts and cats doing the craziest things. However, new research by our research group suggests that the Web may have benefits for those looking to shed the pounds and stay fit, too.

Dr Fiona Johnson and colleagues used data collected from a commercial online weight-loss programme (Nutracheck) to see if individuals monitoring their diet and exercise levels using the software more regularly were more likely to lose weight.  The programme is an online platform which helps users track diet and exercise goals in addition to providing weight charting software, information about nutrition and health and an online forum. With over 3500 subscribers’ data to look at, there was enough information to see which techniques worked best and for whom. What the researchers wanted to find out was whether men and women used the programme differently, and whether any particular parts were more effective than others for losing weight.

The main finding was largely unsurprising – the more often people logged into the programme the more weight they lost, demonstrating the benefits of encouraging users to return frequently to online weight loss programmes.  There were also differences between the genders. Using online support forums was a better route to weight loss for women, whereas recording exercise levels seemed to increase success in men. Looking a little deeper in the data reveals yet more interesting patterns. Overweight or obese men and women that used food diaries the most were substantially more likely to lose over 5 % of their body weight (an amount which is likely to have health benefits) than those who logged their food consumption less diligently. Overweight and obese men seemed to benefit particularly from exercise diaries, with the most engaged being the most likely to shed significant amounts of weight.

We all knew it – consistency is the key. Just sticking to actually using the programme you spent your precious money on will help fight the flab. If you are a man, making note of how often and how long you spend exercising and toning your Adonis body appears to be the route to success. And if you are a woman, chatting about the experience of weight loss and dieting will help even more. So what are you waiting for? Stop looking at crazy cats and get logging!

Reference:

Johnson, F & Wardle, J. (2011) The association between weight loss and engagement with a web-based food and exercise diary in a commercial weight loss programme: A retrospective analysis. International Journal of Behavioural Nutrition and Physical Activity. 8:83 doi:101186/1479-5868-8-83

Susie (susanne.meisel.09@ucl.ac.uk)

Plans to complete a Bowel Cancer Screening test reduce after exposure to the nitty gritty of the test

We all make plans to do things that are good for us, whether it is going for the Sunday morning jog, eating an extra spoonful of greens or saying no to that second (third or fourth!) drink in the pub. The problem is, when the time comes to actually doing whatever it is we’ve been promising ourselves and others to do, all those good intentions seem to disappear as quickly as they arrived.  For the runners among you that have woken only to be faced with a dark and drizzly January morning, you will know what it is that I’m talking about.

So why is it that some people are able to overcome hurdles like the miserable weather, the unappealing sight boiled cabbage and the luring temptation of that extra glass of bubbly? Here at the HBRC we are particularly interested in attempting to answer that question by researching how the perception of time influences people’s behaviour. Some people are always looking towards the future and always want to be prepared for what is to come. Others just want to live for the moment and prefer not to think about what could be round the corner. Interestingly, this appears to be a relatively stable personality characteristic and it is linked to how we feel about behaving in certain ways.

We have recently shown how plans to complete a bowel cancer screening test are affected by time perceptions. Completing a bowel cancer screening kit requires overcoming some pretty immediate obstacles (handling faeces being the most obvious to spring to mind). In addition, the benefits of doing the test won’t be experienced for at least one month (when you hopefully receive a reassuring all-clear letter), or worse, in several years’ time (when you have successfully lived for five years after your bowel cancer treatment). The question we wanted to answer was whether the same people that are able to get out of bed on a cold January morning ready for a 5 mile run, are better able to overcome the short term obstacles of a bowel cancer screening test. In other words, is the ability to look towards the future influencing decisions to complete a bowel cancer screening kit?

We presented some snippets of information to over 200 volunteer middle aged adults (i.e. the group approaching screening age) and asked them after each statement to report ‘how likely it is that you would take part in the screening programme’ (see box 1 for the statements we showed people). Our findings showed how certain parts of the screening programme (e.g. completing it at home) were appreciated, and after finding this out the volunteers increased the strength of their plans. However, once participants were gradually informed about the nitty gritty of the test, people started to waiver. Motivation rapidly declined once people realised they had to collect a sample of faeces and hit a second low when they were informed that the test requires this to be done three times.

Perhaps most interestingly is that people that prefer to live for the moment were more put off by completing it three times and by some photos explaining how to complete the test kit. This enables us to pinpoint the exact stage at which motivation is reduced the most, allowing us to intervene and help people overcome these obstacles.  While this is an exciting finding (even if we do say so ourselves!), it doesn’t explain why those who prefer to stay in the present reduce their motivation faster than others. Is it because they were more put off by the short term obstacles that might affect their short term plans? Or were they just less able to see how beneficial it might be for them in the future? Our analysis seems to suggest that as always, it might be a bit of both. So back to work it is for us, but not before that five mile run I told you about. Anyone?

Reference

Von Wagner, C., Good, A., Smith, S. G., Wardle, J. (in press) Responses to procedural information about colorectal screening using Faecal Occult Blood testing: the role of consideration of future consequences. Health Expectations. DOI: 10.1111/j.1369-7625.2011.00675.x

Sam (Samuel.smith@ucl.ac.uk)