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‘Health Chatter’: Research Department of Behavioural Science and Health Blog



Weight discrimination is chronically stressful

By rmjdsey, on 18 October 2016

Stigmatisation of obesity remains one of “the last acceptable forms of prejudice”.  People with obesity are widely stereotyped as lazy, weak willed and personally to blame for their weight by the media, employers, educators, health care professionals, and even their friends and family.

Facing discrimination can understandably be very stressful in the moment.  Small experiments have shown that asking people to watch a video that stigmatises obesity, or telling them that their body size and shape are unsuitable to take part in a group activity, increases levels of the stress hormone cortisol in their saliva.

But what wasn’t known until now was whether discrimination has lasting effects on stress levels.  This is important because acute (short-term) stress is a protective, adaptive response whereas chronic stress can have a damaging effect on the body.

In a new study published last week in Obesity we explored the relationship between weight discrimination and chronic stress.  The research involved 563 men and women with obesity (body mass index ≥30) aged 50 years and older taking part in the English Longitudinal Study of Ageing (ELSA), a large population-based cohort of middle-aged and older adults living in England.

Rather than measuring levels of cortisol in saliva, which are sensitive to daily fluctuations and short-term factors such as diet, we analysed cortisol levels in hair.  Measuring hair cortisol is a new technique that gives an indication of average levels of cortisol in the body over several months.  Hair grows at approximately 1 cm per month, so the 1 cm of hair nearest to the scalp represents average exposure to cortisol over the last month.

We found that one in eight people with obesity had experienced discrimination because of their weight, ranging from lack of respect or courtesy to being threatened or harassed.  Among people with severe obesity (BMI ≥40), one in three reported discrimination.

Importantly, our findings revealed that average levels of cortisol in hair were 33% higher in individuals who had experienced weight discrimination than those who had not.  People who experienced more frequent weight discrimination had higher hair cortisol levels than those who faced less regular discrimination.

The results of this study provide evidence that weight discrimination is associated with the experience of stress at a biological level.  Because experiencing high levels of cortisol over a prolonged period can have a substantial impact on health and wellbeing, it is likely that weight discrimination contributes to many of the negative psychological and biological consequences of obesity.  In addition, cortisol is known to increase appetite and fat storage, making people who experience weight discrimination more likely to gain weight.


Article link:

Jackson SE, Kirschbaum C, Steptoe A. Perceived weight discrimination and chronic biochemical stress: A population-based study using cortisol in scalp hair. Obesity. First published ahead of print 14 October 2016. doi:10.1002/oby.21657


Is stress making you gain weight? Think again…

By Susanne F Meisel, on 6 January 2012

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