Loss or gain in body weight due to stress is common and can be expected in most of us. However, some factors have been shown to decrease metabolism and promote or trigger weight loss.
The following list is not comprehensive, but it provides a general overview of the common factors that increase or decrease metabolism. Most of these factors also occur in humans, but it’s important to remember that they don’t always occur as quickly in individuals with diabetes. In fact, many of the factors that cause weight gain are common in many populations, including the overweight. For instance, many people can gain weight even after they have a normal BMI. For this reason, weight loss experts recommend that people who are overweight not try to lose weight at any cost.
Hormonal Factors and Lifestyle Factors that Affect Metabolism
Several hormones, particularly those from the adrenal glands and hypothalamus (brain regions that control levels of several hormones responsible for metabolism), influence metabolism in humans. While there are many hormonal factors that change metabolic rate, we tend to hear about the most important ones – leptin (a hormone secreted from the fat cells and that controls bodyweight), adiponectin (another hormone produced by adipose tissues), thyroid (a hormone secreted by the pituitary gland), and ghrelin (another hormone secreted in the stomach and that increases satiety – a good indicator of energy balance), which have been shown to affect how much weight a person will gain, whether they go to bed heavier than they did before, and how much energy they will expend. In most cases when someone loses weight, the most important hormone changing is leptin – a hormone secreted by the fat cells and that regulates the amount of energy stored in the fat cells.
The rest of the body – most notably the muscles, liver, kidneys, testes and brain – is made up of fat tissue. In general, the body is about 80% fat tissue, and less than 10% muscle. The fat cells make leptin from amino acids (not glucose or protein), and the plasma level of plasma leptin is very low within the first hours following a loss of weight. The body uses its fat to absorb nutrition and produce energy from protein. This is why people who regain a very high amount of weight often have a very low plasma leptin level, suggesting their body is using up the protein stores that were once there.
In addition to the role of hunger and satiety hormones, other factors that can have an effect on metabolism and