Resistance training while dieting
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. On its own, lifting burns few calories, so the diet drives the weight loss and the training protects the muscle.
What the science says
- Lifting prevents most diet-induced muscle loss Strong evidence
Sardeli et al.'s 2018 meta-analysis of 6 trials in older adults with obesity found that resistance training 3 times a week for 12–24 weeks prevented about 94% of the lean mass lost with dieting alone, with similar fat and weight loss. Cava et al.'s 2017 review reached the same conclusion across adults.
- Lifting keeps lean mass and strength better than cardio alone Strong evidence
In Villareal et al.'s 2017 NEJM trial, 160 dieting older adults with obesity all lost about 9% of body weight; lean mass fell 2–3% in the resistance and combined groups vs 5% with aerobic training alone, and strength rose about 18–19% vs 4%.
- Lifting alone is a weak tool for weight loss Moderate evidence
In the STRRIDE AT/RT trial (Willis et al., 2012), 119 sedentary adults with overweight trained for 8 months without dieting. Aerobic and combined training reduced body and fat mass more than resistance training, while resistance and combined training increased lean mass.
How to apply it
Keep training the main muscle groups hard and heavy during the diet; you can trim volume if recovery suffers, but keep the loads.
Who should be careful
Resistance training is safe for healthy adults when progressed gradually; energy and recovery are lower in a deficit, so avoid maximal attempts when fatigued. People with joint problems or injuries should have a physician or physical therapist set limits. 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
Do I need to lift weights if I am dieting?
If you want the weight you lose to be fat rather than muscle, yes. A meta-analysis of dieting adults with obesity found lifting 3 times a week prevented about 94% of the lean mass loss.
Will lifting make me lose more weight?
Not much on its own. In the STRRIDE AT/RT trial, aerobic training reduced body and fat mass more than lifting; lifting's job is to keep muscle and strength.
Should I switch to light weights and high reps to 'tone' while dieting?
No. Keep training hard with your usual loads; trials that preserved lean mass used progressive resistance training, and strength rose about 18–19% in Villareal et al.'s trial.
Scientific references
- Resistance Training Prevents Muscle Loss Induced by Caloric Restriction in Obese Elderly Individuals: A Systematic Review and Meta-Analysis
- Aerobic or Resistance Exercise, or Both, in Dieting Obese Older Adults
- Effects of aerobic and/or resistance training on body mass and fat mass in overweight or obese adults
- Preserving Healthy Muscle during Weight Loss
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.
- Rate of weight loss Moderate evidence
For people who lift, losing about 0.
- 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.
- 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.