A common complaint of people who struggle to lose weight is that previous dieting has ruined their metabolism. Metabolic adaptation, also known as adaptive thermogenesis or starvation mode, may be an influencing factor in the development of obesity but it is not solely responsible and can be overcome with sufficient dietary change and exercise. Such change may require more effort, commitment and determination than the failed dieter has bargained for.
While it may be the case that weight maintenance is challenging, the metabolism is never ruined. A lower metabolic rate can be overcome with additional exercise that helps to build muscle mass.
In response to starvation, metabolic rate slows to compensate for the calorie deficit. The extent to which metabolic rate decreases during calorie restriction and weight loss is highly variable between individuals. Most studies show that obese people have a higher total and resting metabolic rate compared to normal-weight individuals, because it takes more energy to move a bigger body. They also have more tissue, both muscle and fat, which is metabolically active to different degrees.
Interestingly, studies show that people who have previously been overweight or obese and then lost weight to reach a healthy level have a metabolic rate that is 3-8% lower than those who have never been overweight; other studies show that, as people gain weight, their metabolic rate increases proportionally. This means it may be slightly harder for previously obese people to maintain their new healthy weight, but this is something that can be overcome with a bit of extra exercise.
Is it better to eat little and often?
Some people believe that eating six small meals a day, and splitting your daily calories into smaller groups, is better than eating the traditional three. This is linked to the knowledge that each time you eat there is a rise in metabolic rate through the thermic effect of food.
However, there is very little evidence to suggest that breaking up meals this way leads to an increase in net metabolic rate. This is because the thermic effect of food is directly proportionate to the energy consumed in a meal.
The foods you eat in one sitting or in two will still have the same effect on your metabolism. There is though, some evidence to suggest that how you consume your calories may impact on other aspects o your health. In one small study, 11 obese women were divided into two groups. They all consumed the same number of calories a day, but one group consumed these in two meals and the other in six meals. Both groups lost around the same amount of weight, but those who ate six meals a day retained ore muscle mass whereas those who ate two meals a day had improved levels of cholesterol and better blood-sugar control.
Comments
Post a Comment