There are hormonal reasons why people who lose weight feel hungrier after their weight loss than before. That makes it more difficult to keep the weight off. Photo: Colourbox

Why you feel hungrier after you lose weight

Feeling hungrier and eating less for the rest of your life may be the price to pay once you’ve shed those extra pounds.

Obesity continues to be growing problem in the developed world, and Norway, where one in four people is overweight, is no exception.

Research in both adults and children shows that you don’t get fat from being inactive, you become inactive because you get fat,” says Catia Martins, associate professor at NTNU.

A recent study helps illuminate why it can be so difficult to maintain a healthy weight after substantial weight loss. The study, just published in the American Journal of Physiology, Endrocrinology and Metabolism, studied appetite in patients who participated in a comprehensive 2-year weight loss programme, and found clues as to why maintaining weight loss long term is so difficult.

After two years all the participants had lost weight. But everyone was also hungrier than when they started. The key appears to be in the balance between hunger and satiety hormones in people who have lost a lot of weight.

Gold standard obesity treatment

Proper diet and exercise are the keys to maintaining weight loss. If you also realize that a hormone is what’s making you feel hungry, it may be easier to cope with the hunger pangs, says Martins. Photo: Colourbox

“We gave 34 patients with morbid obesity the gold standard in obesity treatment over a period of two years,” said Catia Martins, an associate professor in the Norwegian University of Science and Technology’s (NTNU) Department of Clinical and Molecular Medicine.

Patients started out weighing 125 kilograms on average. They were first admitted for three weeks at a treatment centre that specialized in addressing obesity, where they had to exercise regularly and undergo different tests. Patients also received nutritional education and had conversations with psychologists.

This format was repeated approximately every six months.

Participants lost an average of 11 kilos after two years. In the first three weeks they lost roughly five kilos.

Two out of ten manage to keep weight down after programme

According to Martins, most people with obesity are able to lose weight, even on their own, but research shows that only 20 per cent manage to maintain the new lower weight.

Keeping the kilos off

The United States maintains a large register of people who have lost weight through lifestyle change, where weight loss was at least 14 kilos and was maintained for at least one year. On average, people lost 32 kilos and maintained their weight loss for six years.

People who managed to maintain their weight loss:

  • Ate food with few calories and little fat
  • Weighed themselves once a week
  • Ate breakfast every day
  • Did an hour of exercise every day, such as going for a walk
  • Realized their lower-weight bodies needed significantly fewer calories than their pre-weight-loss bodies.

From a purely biological perspective, two factors are at play: human evolution and the body’s ability to ensure its survival. One of these is a hormone. The second is the body’s ability to conserve energy.

First, let’s consider the hormone.

Hunger hormone increases when dieting

When we lose weight, the stomach releases greater amounts of a hormone called ghrelin. This hormone makes us feel hungry.

“Everyone has this hormone, but if you’ve been overweight and then lose weight, the hormone level increases,” says Martins.

The disappointing news about ghrelin is that the level does not adjust over time. The study shows that the level of ghrelin in the study participants remained high throughout the two years.

Martins says this means it’s likely that people who have been overweight will have to deal with increased hunger pangs for the rest of their lives.

The body resists dieting

In addition to biological factors, food is social. We don’t eat just because we’re hungry. We eat at family celebrations, and sometimes we eat because we’re bored or sad, says Martins.

On to the other mechanism: the body’s ability to conserve.

“A person who’s been very obese has needed more energy just to breathe, sleep, digest food or walk. When the body loses weight, less energy is needed for these basic functions, simply because the body is lighter,” says Martins.

Some people also go into saving mode.

“Someone who has weighed 80 kilos their whole life can eat more than a person who is 80 kilos after losing weight. The difference in the amount of food is about 400 calories – the amount of a good breakfast or four bananas,” says Martins.

In other words, people who have lost weight need less energy to maintain their new and lighter bodies. And yet they feel hungrier, because the body is trying to get that weight back. Just to be on the safe side.

Obesity should be treated as a chronic disease

Diet has the greatest impact on weight loss. Dieting and exercising together give the best weight loss results. Photo: Colourbox

“It’s important to know which physiological mechanisms resist weight loss. Of course there are individual differences. People can lose motivation and have trouble following the diet and exercise advice. All of this makes it difficult to maintain the new lower weight,” says Martins.

According to the study, the feeling of satiety after a meal also increased, but the feeling of hunger increased more.

“Obesity is a daily struggle for the rest of one’s life. We have to stop treating it as a short-term illness by giving patients some support and help, and then just letting them fend for themselves,” says Martins.

She believes that obesity needs to be handled as a chronic disease in line with other chronic illnesses.

For example, Martins says, a person with type 2 diabetes receives a lot of help and close follow-up over time. That’s the way we have to work with obesity as well. Otherwise, it can be very difficult to keep your weight down on your own.

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Reference: Impact of weight loss achieved through a multidisciplinary intervention on appetite in patients with severe obesity. Silvia R Coutinho, Jens F. Rehfeld, Jens J. Holst, Bård Kulseng, and Catia Martins. American Journal of Physiology-Endocrinology and Metabolism. 23 January 2018, doi:10.1152/ajpendo.00322.2017