Many people who want to lose weight go on a crash diet, but then find they put the weight back on over the next few months.
Weight regain after an initial successful weight loss in obese people is an important and unsolved problem. Until recently no research has identified an effective way to maintain a healthy weight loss.
Julie Meek lecturer in Nutrition at Murdoch University said people tend to gradually return to their former ways after a period of restrictive eating.
“Chronic dieters develop a pattern of repeated dieting and weight gain. The cycle is more psychological and physiological,” she said.
Researchers led by Professor Signe Torekov at the Department of Biomedical Sciences at University of Copenhagen tested four different treatments following a diet-induced weight loss to demonstrate how it may be possible for obese people to maintain weight loss, long-term.
The volunteers lost an average of 13kg on an eight-week low calorie diet. They were then randomised into four groups. One group undertook an exercise regime plus a placebo, a second group were given Liraglutide, an appetite suppressant, a third group took both the suppressant and exercise and the control group who were given only the placebo.
Liraglutide, an analogue to the appetite-inhibiting hormone GLP-1, is marketed as Saxenda® and is only available in Australia with a doctor’s prescription.
After one year the group with exercise alone and the group with appetite suppressant alone maintained the weight loss of 13kg. The placebo group gained half of the weight back with deterioration of all health risk factors, with some people developing Type 2 diabetes and heart disease.
The most dramatic improvements occurred in the combination group, which followed the exercise program and received medication. This group lost on average an additional 16kg of weight over one year. The health benefits included twice the loss of fat mass while preserving muscle mass, higher fitness ratings, reduced blood sugar and improved quality of life.
The two groups that exercised increased their fitness rating, lost fat mass and gained muscle mass. This could indicate a healthier weight loss than for people who had only lost fat mass, without increasing their fitness rating.
“It is an important aspect to highlight, as you do not necessarily get a healthier body from losing weight if, at the same time, you lose a lot of muscle mass,” says Professor Torekov.
“It is great news for public health that a significant weight loss can be maintained with exercise for approximately 115 minutes per week performed mostly at vigorous-intensity, such as cycling. By combining exercise with obesity medication, the effect is twice as good as each of the individual treatments.
“This is new knowledge for doctors, dietitians and physical therapists to use in practice.
“The problem is that people are fighting against strong biological forces when losing weight. The appetite increases simultaneously with decreased energy consumption, and this counteracts weight loss maintenance.
“We all have an appetite-stimulating hormone, which increases dramatically when we lose weight, and simultaneously the level of appetite-suppressing hormones drop dramatically. In addition, a weight loss can provoke loss of muscle mass, while the body reduces the energy consumption,” he said.
“Most nutritionists in Australia prefer not to recommend appetite suppression tablets, although psyllium husks are often suggested as aids to weight loss as they provided a feeling of fullness in the stomach,” said Ms Meek. “People tend to override their hunger symptoms.”
Consumer group Choice said the current evidence for the effectiveness and safety of over-the-counter weight loss pills is pretty sketchy.
Professor Torekov’s research was published in the New England Journal of Medicine, early this year.