During the periods while the weight is off, there are many health benefits to be had, such as reduced blood pressure, lower levels of triglycerides (a type of bad cholesterol in the blood), improved cholesterol ratios, and better cardiovascular health, as well as better mental health and quality of life.
When it comes to measuring those health benefits though, there is a great deal of variability, depending on factors like how much weight you lose and your previous level of obesity. “Those who are already metabolically unhealthy with insulin resistance, hypertension, maybe prediabetes, don’t profit as much as others from 10 per cent of weight loss,” says Prof Stefan. “They need much more – 15 to 20 per cent.” For yo-yo dieters, when the weight comes back, their previous risk levels return.
One of the most important benefits of yo-yo dieting, however, is that it can be one step closer towards permanent weight loss. We can choose to experience weight regain as a failure or as proof that, for a while, it was possible – and next time, do better. “People who are overweight should not be discouraged from attempting to lose weight, even if they find it difficult to maintain in the long term,” Prof Stefan’s paper concluded. “Unsuccessful weight-loss attempts are not harmful, but giving up altogether may be.”
There is, however, one caveat. “The main message is that not losing weight at all is a worse outcome,” says Prof Stefan. “But the cells that produce insulin – which are so important when it comes to risk of diabetes – are very sensitive. They can’t reproduce, they can only decline, and there is some data which suggests that weight cycling can be damaging for them. We need further studies to be sure whether or not this is a problem.”
Breaking the cycle: How to lose weight and keep it off
“Does it matter how we lose weight? Are some methods more permanent than others? There has been a lot of research into that question,” says Prof Stefan. “Bariatric surgery is the most effective. In most cases, there’s not much weight regain – although it has its health problems. There’s a risk of hyperglycaemia after surgery, for example. You’ll need to take vitamins all your life.”
Regarding the use of weight-loss drugs, it’s estimated that all the weight lost will be regained within 1.7 to two years of discontinuing the drug. That said, fad diets don’t fare much better. “Quick and aggressive weight loss through a very low-calorie diet like 800 calories a day for three months, results in a large amount of weight loss, but after one year, it has resulted in the highest weight gain,” says Prof Stefan. “It’s effective for the first eight weeks, but not the long term.”
So what’s the answer? “The most successful for continuous weight loss is to lose small amounts, maybe half a kilo a week, through diet and exercise. Then the regain is less,” says Prof Stefan. “Slow, steady weight loss is ideal, and the earlier you lose weight, the better.” The later you leave it, the more weight you gain, the more hungry you feel and the more primed your body becomes to return to that state.