Rate of weight loss
For people who lift, losing about 0.5–1% of body weight per week keeps more muscle and strength than crash dieting. For people with obesity, losing weight faster does not cause more regain than losing it slowly; what matters most is what happens afterwards.
What the science says
- Slower loss preserves lean mass in athletes Moderate evidence
Garthe et al. (2011) had 24 elite athletes who lifted four times a week lose weight at about 0.7% vs 1.4% of body weight per week. Both lost about 5.5% of their weight, but the slower group gained 2.1% lean mass and more strength, while the faster group's lean mass did not change. The sample was small and highly trained.
- 0.5–1% per week is the usual target for lifters Moderate evidence
Helms et al.'s 2014 evidence review for natural bodybuilders recommended setting calories to lose about 0.5–1% of body weight per week to maximize muscle retention, based on the available trials.
- Fast loss is not regained faster Moderate evidence
Purcell et al. (2014) randomized 200 adults with obesity to a 12-week rapid or a 36-week gradual program aiming at 15% weight loss. More rapid dieters reached the target (81% vs 50%), and both groups regained about 71% of the lost weight by roughly 3 years, so the speed of loss did not change regain.
How to apply it
Choose a rate that matches your body fat and training goals, and check it against the weekly average weight.
Who should be careful
Very fast weight loss raises the risk of muscle loss, fatigue and gallstones, and aggressive diets can trigger disordered eating in susceptible people. Anyone with diabetes, high blood pressure or another obesity-related condition, a history of eating disorders, who is pregnant or breastfeeding, or who is considering weight-loss medication should plan weight loss with a physician or registered dietitian; this page gives no drug advice.
Frequently asked questions
How fast should I lose weight?
About 0.5–1% of body weight per week. Lifters who want to keep muscle and strength do best toward the slower end, around 0.5–0.7%.
Is weight lost quickly always regained?
Not more than weight lost slowly. In Purcell et al.'s trial, rapid and gradual dieters both regained about 71% of the lost weight after roughly 3 years.
Why does slow loss help muscle?
In Garthe et al.'s study of athletes who lifted, losing 0.7% per week led to lean mass gains, while losing 1.4% per week did not, although total weight lost was similar.
Scientific references
- Effect of two different weight-loss rates on body composition and strength and power-related performance in elite athletes
- The effect of rate of weight loss on long-term weight management: a randomised controlled trial
- Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation
More on weight loss
- Calorie deficit Strong evidence
Fat loss requires eating fewer calories than you burn for weeks to months; every diet that works does this, whatever it is called.
- High-protein diet while dieting Strong evidence
Eating more protein during a calorie deficit helps keep lean mass and gives a small extra fat loss compared with a standard-protein diet of the same calories.
- Resistance training while dieting Strong evidence
Lifting weights during a diet makes much more of the weight you lose come from fat instead of muscle, and it keeps or raises strength.
- Cardio for weight loss Moderate evidence
Cardio helps fat loss, but at typical doses it produces only a couple of kilograms on its own; clinically meaningful loss takes high volumes (more than about 250 minutes a week) or a calorie deficit alongside it.
- Diet breaks and refeeds Moderate evidence
Planned periods at maintenance calories in the middle of a diet are at least as effective as dieting continuously and may make the diet easier to tolerate.
- Intermittent fasting Moderate evidence
Intermittent fasting (5:2, alternate-day fasting or time-restricted eating) works for weight loss about as well as an ordinary calorie-controlled diet, but not better.