Effect of a Long Bout Versus Short Bouts of Walking on Weight Loss During a Weight-Loss Diet: A Randomized Trial by A. Madjd , M. A. Taylor, A. Delavari, R. Malekzadeh, I. A. Macdonald, H. R. Farshchi see https://pubmed.ncbi.nlm.nih.gov/30737894/

The above study compared the effect on weight loss of physical activity in 2 short bouts (2*25 minutes) versus 1 longer bout (50 minutes) per day, 6 days a week. The subjects with the 2 short bouts lost more weight.

Another study compared 50 min per day physical activity, 6 days per week (300 min/week) with longer duration 100 min/day PA, 3 days a week. In this case the lower frequency group lost more weight.

My conclusion: find a way to exercise that you enjoy and works with your lifestyle. Ideally one that support healthy eating patterns. If you find that you overeat after long bouts of exercise it may be better to break it into small bouts.

The current recommendations for exercise

• Maintain and improve health 150 minutes per week
• Prevention of weight gain 150-250 minutes per week
• Promote clinically significant weight loss 225-420 minutes per week
• Prevention of weight gain after weight loss 200-300 minutes per week

The type of exercise is important also. Aerobic exercise compared to resistance training seems to support weight loss but only at very high levels unless combined with calorie restriction see https://www.vox.com/2016/4/28/11518804/weight-loss-exercise-myth-burn-calories

The above article concludes the following

• It is unlikely the exercise alone will result in significant weight loss. It is necessary to calorie restrict as well – probably because it is so easy to compensate for additional calories burned from exercise
• Exercise is very important to maintain weight after significant weight loss and it needs to be at higher levels that is required normally to maintain health.

The article Stress and Obesity by A. Janet Tomiyama, in the Annual Review of Psychology looks at the pathways that connect obesity and stress and gives a summary in the abstract of there 3 main areas

• stress interferes with cognitive processes 1. executive function 2. self-regulation
• stress can affect behavior by 1. inducing overeating 2. decreasing physical activity 3. shortening sleep.
• stress triggers physiological changes 1. in the hypothalamic-pituitary-adrenal axis 2. reward processing in the brain 3. possibly the gut microbiome 4. stress can stimulate production of biochemical hormones and peptides such as leptin, ghrelin, and neuropeptide Y.

Obesity itself can be a stressful state due to the high prevalence of weight stigma. This article therefore traces the contribution of weight stigma to stress and obesogenic processes, ultimately describing a vicious cycle of stress to obesity to stigma to stress. Current obesity prevention efforts focus solely on eating and exercise; the evidence reviewed in this article points to stress as an important but currently overlooked public policy target.

Stress and Obesity by A. Janet Tomiyama, in the Annual Review of Psychology

Some thoughts

• Learning to cope with stress in healthy ways is an important skill
• It may be worth examining sources of stress. Managing stress levels and sources of stress may be an important solution to combating obesity.

Consider: which of the above stress/food mechanisms are most significant for me and which of them I can at the present time do something about ie cognitive process changes, behaviour changes and physiological changes.