The process of losing weight for many – real torture. Careful counting of calories, efforts to remove body fat in problem areas, the search for effective diets and exercises. Everyone is well aware of the basic rule of losing weight – eat fewer calories than your body uses (in other words, eat less and move more). However, even those who follow this rule sooner or later face difficulties – weight does not want to go further (the so-called plateau effect). And for those who give up, a more serious problem awaits – return of lost kilograms. What role does adaptive thermogenesis play in this process, estet-portal.com will tell in this article.
Energy costs of the body – first step towards understanding adaptive thermogenesis
To understand why the process of losing weight slows down over time, despite following the original plan, you need to know what the body spends energy on. The energy costs of the body are distributed as follows:
- Resting energy expenditure is the amount of calories that the body needs to maintain life at rest, namely:
- for breathing;
- for heartbeat;
- for the activity of internal organs and tissues.
At rest, we burn approximately 60-75% of our daily calories, but for active people, this percentage can be approximately 50%.
- The energy cost of physical activity is the amount of calories that the body spends on any bodily movement, not just sports. The percentage of this calorie expenditure is approximately 17-32%, but, as in the case of energy expenditure at rest, this figure can be higher in physically active people. This group includes:
- training activity (active planned sports);
- non-training activity (body movements that we make throughout the day);
- Thermic effect of food (calories expended on digestion and assimilation of food).
The diagrams below compare energy expenditure in the body of a physically inactive (left) and active (right) person:
Yellow – at rest; pink – for physical activity; green – to digest food.
Read also: Metabolic flexibility: make your body burn fat
What is adaptive thermogenesis and what is its role in weight loss?
Weight loss is known to be accompanied by a reduction in energy expenditure. This happens for one simple reason: by moving less weight, we spend less force. However, how proportionate is such a reduction?
Adaptive thermogenesis – change in energy expenditure pattern after sudden and/or prolonged overeating or undernutrition.
Rudolf Leibel and his team have made significant progress on this issue by calculating the difference between actual energy consumption and calculated values. Such studies have shown that weight loss contributed to increased resting energy expenditure.
The study, led by Rudolf Leibel (Columbia University), also involved volunteers who lost at least 10% of their initial weight and maintained the result for at least a year.
Participants were divided into several groups (for both men and women):
- volunteers who didn't lose weight;
- volunteers who lost 10% or more of weight and maintained the result for 5-8 weeks;
- Volunteers who have lost 10% or more of weight and maintained the result for at least a year.
For the duration of the study, participants lived on the study site and ate a liquid diet (40% fat, 45% carbohydrate, and 15% protein). Scientists adjusted the amount of calories consumed by volunteers so that their weight remained stable.
Thus, under conditions of stable weight, daily energy expenditure should also have remained unchanged.
So, the graph clearly shows that it is the people who have recently lost weight who spend the least calories per day, while they spend the least calories on physical activity.
Next, the scientists compared the results obtained with the calculated ones (the designations are the same):
As it turned out, those who lost weight spent fewer calories than was calculated, and the results of volunteers who did not lose weight almost coincided with the calculated ones.
How to prevent weight gain after losing weight?
The results of the above study show that the reduction in weight and metabolic rate exceeds what would be expected based on weight loss alone. At the same time, this difference persists even for people whose weight has been stable for more than a year.
Since a decrease in metabolism of about 150 kcal per day is not significant, the reason for the decrease in energy expenditure lies precisely in the subconscious decrease in physical activity, and non-exercise.
Read also: How Nordic Walking can help you lose weight
Studies have shown that at a certain stage of weight loss, due to a decrease in physical activity and a slight slowdown in metabolism, a person spends more than 400 calories less per day.
So that adaptive thermogenesis does not cause weight gain after weight loss, it is necessary to increase the level of conscious physical activity, and not necessarily in the form of training.
Even an ordinary walk, which you will spend an hour a day (provided that you have not done this before) will help maintain a stable weight after losing weight. Therefore, try to use your free time for a pleasant and active pastime.
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