Anyone who has ever been on the line and started it again in the long run knows what it is: the yo-yo effect. How is it that most people usually return to their old weight after a line test, or worse: get heavier than ever before? Seven questions to Professor of Functional Genetics Edwin Mariman.
How can many people get heavier after a diet?
“About 80 percent of people will be back to their old weight within one to two years. Unable to change lifestylehabits is often a cause. And stress often revolves around food. But our research has shown that biological processes also play an important role.”
What happens then?
“When you’re on the line, the fat cells start behaving differently. They release other amounts of hormones. Less leptin, for example, a hormone that regulates the feeling of satiety. This makes you hungrier and you’ll eat more.”
“What also plays a role is cell stress. Because less energy comes in, the fat cells shrink, but the “skeleton” that sits around these cells does not shrink so quickly. This creates tension in the cells and wants to grow again by turning the “host” on to food. As a result, you lose less or even arrive. The body is destined to stack energy again after losing weight.”
“Losing weight has a positive effect on insulin sensitivity. If you’re overweight, it’s always good to get back on the line.”
Edwin Mariman, Professor of Functional Genetics
Does it matter if you waste quickly or slowly?
“Our own study comparing a crash diet with a ‘slower’ diet showed that the rate or degree of weight gain after diet was not different. A surprise, because we had thought that the cell stress would be greater in a crash diet and that the crash diet group would arrive faster and more.”
Is Jo-Joing unhealthy?
‘That’s not 100 per cent clear. About half of the studies show that yo-yoing eventually leads to a slightly higher weight, but not to a worsening of insulin sensitivity, something that can eventually lead to the development of type 2 diabetes.”
“The weight loss itself has a positive effect on insulin sensitivity. If you’re overweight, it’s always good to get back on the line.”
How do you prevent the yo-yo effect?
“First, by choosing a healthy diet and maintaining it after you reach your target weight. My colleague, Professor van Baak, has compared several studies. This shows that there really is only one thing that helps keep a low weight: base your diet on a higher protein content.”
What do these proteins do?
“Proteins create the feeling of satiety, besides, when losing weight is not only about what you eat, but also about what you burn. You need muscles and proteins are building materials for this. Start losing weight to limit muscle loss. And move! With exercise, you train your muscles and turn them on to burn.”
Prof. Edwin Mariman is Professor of Functional Genetics at Maastricht UMC+