Can stress cause weight gain?

School Of Nutrition Posted Aug 14, 2014 Future Fit Training


We all know that obesity is a growing health concern worldwide. Research studies have long suggested that stress can lead to an increased risk of weight gain.

Can stress cause weight gain?

In the UK, adult obesity rates have almost doubled in the last 20 years, with 24.4% of men and 25.1% of women now being obese [1].Unfortunately, stress seems to be a way of life in the 21st century. So could stress be making us fatter?

Stress-induced eating may be one factor contributing to the development of obesity. While the immediate response to acute stress can be a temporary loss of appetite, chronic stress on the other hand can be tied to an increase in appetite, a greater preference for energy-dense foods, namely those that are high in sugar and fat [2], and stress-induced weight gain.

When we are stressed our neuro-endocrine system releases the hormones needed to help us ‘fight or flight’ our stressors. Stress hormones act by mobilizing energy from storage to muscles, increasing heart rate, blood pressure and breathing rate as well as shutting down metabolic processes such as digestion, reproduction, growth and immunity.

The hormones released when we are stressed include adrenalin - which gives us instant energy - along with corticotrophin releasing hormone (CRH) - which can suppress appetite in the short term. CRH also stimulates the release of cortisol, whose primary  functions are to spare available glucose for the brain, generate new energy from stored reserves, and divert energy from lower-priority activities (such as the immune system) in order to survive immediate threats or prepare for exertion. As cortisol helps replenish the body after the stress has passed, it can remain elevated for longer and leads to an increase in appetite.

To make matters worse, as the main fuel our muscles need to ‘fight or flight’ is sugar, we tend to crave sugary carbohydrates after stressful situations. A high intake of sugar leads to a corresponding surge in insulin levels, which drive the sugar from the blood to our muscles. However, high levels of insulin also increase the rate of lipogenesis, or fatty acid synthesis, and subsequent fat deposition [3]. This can lead not only to weight gain but also to the storage of ‘visceral fat’ around the middle section of the body. Visceral or abdominal fat has been linked to an increased risk of type 2 diabetes and cardiovascular disease [4].

Furthermore, a recent study has suggested that stress may also promote weight gain by slowing your metabolism [5]. Researchers enrolled 58 middle-aged women to eat high-fat meals on two separate days while their metabolism was monitored. Compared to women without stress in the study, stressed-out women burned both calories and fat more slowly for seven hours after eating the equivalent of an average fast-food burger meal. The difference was 104 calories, which is no big deal on a daily basis, but over the course of a year that could add up to 11 pounds. These findings suggest that stress could affect the physical processes that lead to obesity, including a lower resting energy expenditure and fat oxidation (burning of fat). The researchers also found that women who had been stressed the day before had higher insulin levels, which promote fat storage and are associated with weight gain. However, the results don’t reveal how the body might respond to low-fat or balanced meals. And it is also not clear if the findings would apply to men also. Men tend to have higher lean body mass, which is one of the factors that influences resting energy expenditure, so clearly more research is needed.

In addition, eating in response to stress can also be a learned habit. It may be that the body’s initial response to high levels of cortisol drives you to eat sugary foods. However, once you realise that there is comfort in eating sugary foods, you will quickly learn a behavioural response that you will more than likely repeat every time you feel stressed.

Whether your urge to eat at times of stress is driven by hormones or habit, the good news is that there are ways to interrupt this cycle and stop the weight gain. Here are some recommendations:

1. Get plenty of exercise. Not only does exercise keep the heart healthy and modulate insulin and sugar levels, but it also depletes stress hormones and releases mood-enhancing chemicals (endorphins) which help us cope with stress better.

However, exercising too hard can actually raise cortisol levels and increase stress. So make sure to choose an activity that you really enjoy and keep your workout to a length of time you find comfortable.

2. Take time out to relax. Activities that make you feel relaxed and calm can work much like exercise does to produce brain chemicals that counteract the effects of stress. For some it could be yoga. Others may prefer meditation. Or it could be something as simple as cuddling up on a sofa with a good book or watching your favourite movie.

3. Get plenty of sleep. The release of cortisol as well as the secretion of hormones that play a major role in appetite regulation, such as ghrelin and leptin, is partly dependent on sleep timing, duration and quality [6]. This is why when we don't get enough sleep, we feel hungrier and less satisfied with the food we do eat.

4. Eat a balanced diet. Eat regular meals that include foods from all the food groups and snack on high fibre, whole-grain foods. As well as keeping you satiated this helps keep blood sugar levels steady throughout the day, which in turn will lower insulin production and eventually reduce cortisol levels - all helping to control appetite and weight.

5. Avoid caffeine and alcohol. Regularly drinking coffee andother caffeine-laden drinks may promote weight gain by stimulating cortisol production. It is also recommended not to drink too much alcohol as it can affect blood sugar and insulin levels.

CONCLUSION

It is clearly evident that stress can lead to weight gain, although more research is needed to ascertain the exact mechanisms involved.

If you find yourself chronically stressed out, make sure that you take time out to relax and get plenty of sleep as well as some exercise to help reduce stress levels. By following a reduced-calorie, yet balanced diet, you will also stop the weight gain and maybe even lose some extra pounds.

Written by Victoria Trowse 

REFERENCES

1. Statistics on Obesity, Physical Activity and Diet - England, 2014. http://www.hscic.gov.uk/catalogue/PUB13648

2. Torres, SJ and Nowson, CA. (2007). Relationship between stress, eating behavior, and obesity. Nutrition. 23 (11-12): 887-94.

3. Kersten, S. (2001). "Mechanisms of nutritional and hormonal regulation of lipogenesis". EMBO Rep. 2 (4): 282–6.

4. Matsuzawa, Y. (2008). The role of fat topology in the risk of disease. Int J Obes (Lond). 32 (Suppl 7): S83-92.

5. Kiecolt-Glaser, JK, et al. (2014). Daily Stressors, Past Depression, and Metabolic Responses to High-Fat Meals: A Novel Path to Obesity. In Press.
DOI: http://dx.doi.org/10.1016/j.biopsych.2014.05.01

6. Leproult, R and Van Cauter E. (2009). Role of Sleep and Sleep Loss in Hormonal Release and Metabolism. Endocr Dev. 17: 11-21.

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