Is yo-yo dieting, repeatedly gaining and losing weight, bad for me?
Yo-yo dieting is probably less harmful than is often thought, but whether it is the cause of health damage, or whether underlying poor health is the real explanation, remains uncertain. A stable weight is the most achievable goal, and exercise helps more than simply counting calories.
Yo-yo dieting may increase the risk of early death: fifteen studies combined show a 45% higher risk in people with the greatest weight fluctuations, compared with people whose weight remains stable. However, one important caveat: a large British study found that this association largely disappeared once researchers accounted for pre-existing illnesses and unhealthy lifestyle habits. It is probably not the yo-yo dieting itself, but the unhealthy circumstances surrounding it, that plays the greatest role.
The popular idea that yo-yo dieting causes you to store more fat or permanently slows your metabolism does not hold up well. A 2024 review of 23 studies shows that in healthy adults, fat mass, muscle mass and metabolism do not worsen in the vast majority of cases as a result of yo-yo dieting. Earlier research did suggest that focusing solely on calories, without exercising, temporarily lowers resting metabolic rate, but exercise can counteract this.
Where yo-yo dieting does remain a concern is cardiovascular health. With each new cycle of losing and regaining weight, blood pressure, blood sugar and blood fats fluctuate along with it. This can place extra strain on the body, especially in people who are naturally at a healthy weight but repeatedly go on diets. People of normal weight who diet repeatedly appear in some cases to develop more cardiovascular risk factors than people with excess weight who yo-yo diet.
There are also indications of a link with eating problems and dissatisfaction with life. Whether yo-yo dieting causes these problems, or whether people who are already dissatisfied are more prone to yo-yo dieting, cannot be determined from the available research. For children and young adults there is the additional concern that repeated dieting at a young age may in the long run actually trigger extra weight gain, although that association has not been conclusively proven either.
This answer draws on one overview of fifteen studies, one large British cohort study, a systematic review of 23 studies, and a number of individual review articles. The researchers themselves point to important limitations: there is evidence that selectively positive results have been published, which means the 45% finding may be an overestimate, and most studies do not distinguish between voluntary and involuntary weight loss, which strongly clouds the results. The evidence on body composition is the most robust; the evidence on mortality and psychological effects is less convincing.
I am overweight: what will losing weight do for me?
Losing weight delivers measurable health gains from as little as 5% weight loss: better blood sugar, lower blood pressure and less pressure on your knees. Combine diet with strength training to preserve muscle mass and reduce the risk of weight regain.
Why is it harder for me to lose weight than it used to be?
Ageing lowers your energy expenditure through muscle loss and a slower metabolism, making weight loss objectively harder. Strength training two to three times per week is the best-supported way to slow that process and support weight loss, ideally with professional guidance.
Does the timing of meals throughout the day affect your weight?
When you eat matters: meals earlier in the day appear more favourable for your metabolism than eating late, although the effect varies from person to person and the strongest evidence is still based on short-term studies.
How bad is sitting for too long for your blood sugar and metabolism?
Sitting for long uninterrupted periods noticeably impairs your blood sugar and metabolism, but short breaks of 2-3 minutes of movement every 20-30 minutes already undo a large part of that damage.
What are effective ways to lose weight?
The combination of eating fewer calories and exercising for more than 250 minutes per week is the most proven effective approach; add behavioural support if sustaining it proves difficult, and discuss medications or surgery with your doctor if lifestyle changes alone are not producing sufficient results.
Does drinking water help with weight loss?
Drinking water probably helps with weight loss, especially when done before meals or used to replace sugary drinks. The effect is modest and works best as part of a broader diet.