Weights or cardio for weight loss: which is better for women?

If you only care about the number on the scale, cardio has the edge: in head-to-head trials it lowers body weight and fat mass more than lifting does. Lifting does something cardio doesn't, which is help you keep (and often build) muscle while you lose fat. The best overall change in body composition comes from doing both, on top of a modest calorie deficit, which is usually the bigger lever for the scale.

Below is what the main studies found, what each type of training is good for, and a sample week for the gym or home.

The short version

What happens when you compare them head to head

The clearest comparison comes from a US trial called STRRIDE AT/RT, published in 2012. Researchers split 119 inactive adults with overweight or obesity into three groups for eight months. 68 of them were women, the average age was about 50, and the average BMI was about 30.

• Lifting only: 3 days a week, 3 sets of 8 to 12 reps on about eight machines covering the whole body.
• Cardio only: about the energy of jogging 12 miles a week, at a moderately hard to hard effort, on a treadmill, elliptical or bike.
• Both: the full lifting program plus the full cardio program.

Nobody was asked to change what they ate, and food records showed intake didn't change much in any group. Here's what changed on average:

Three things stand out.

1. Cardio moved the scale and fat mass more. The cardio group was prescribed about 2 hours 15 minutes a week, less than the lifting group's 3 hours, and still lost more fat. The authors concluded that, of the three, cardio was the best choice for lowering fat mass and body weight.
2. The lifting group got slightly heavier. The gain was mostly lean mass, and their body fat percentage still fell a little. Judged by the scale alone, it would have looked like failure.
3. Doing both gave the best body composition. The combined group lost the most fat and the most from its waist, and added muscle. But it took about twice the training time and didn't lose more total weight than cardio alone.

Some cautions. These are group averages, and individuals varied a lot. Men and women were analyzed together, and the analysis only included people who finished with complete measurements, which can make results look better than they would across everyone who started. And because nobody changed their diet, eight months of regular training moved average body weight by less than 2 kg (about 4 lb). That point matters more than the cardio-versus-weights question.

Why exercise alone moves the scale slowly

A 2021 overview pulled together 12 systematic reviews covering 149 studies of adults with overweight or obesity. Compared with no exercise, exercise programs led to average weight loss of about 1.5 to 3.5 kg (3 to 8 lb) and fat loss of about 1.3 to 2.6 kg (3 to 6 lb). Exercise also reduced visceral fat, the fat stored around the organs. Real effects, just not large ones.

The amount of activity matters. The American College of Sports Medicine (ACSM) said in its 2009 position stand that 150 to 250 minutes a week of moderate activity brings only modest weight loss, and that more than 250 minutes a week has been linked to clinically meaningful loss. Its 2024 consensus statement says the benefits for body weight may be greatest once you build up to at least 150 minutes a week of moderate activity, with more bringing more benefit.

Keeping weight off afterward is less clear than you might expect. The one review in the 2021 overview that looked at it found no clear effect of exercise. ACSM's 2009 stand noted that observational studies link more than 250 minutes a week to better maintenance, but that no well-designed randomized trials had tested it.

Exercise does add to weight loss when paired with a moderate diet, according to the 2009 stand. But since exercise alone moves the scale modestly, for most women the bigger lever is eating a little less. Our guide to the calorie deficit for women explains how to set a moderate one and adjust it. Exercise then shapes how much of what you lose is fat and how much is muscle.

What cardio does well

• It uses more energy per session. That's why it moves the scale more when diet stays the same.
• The type matters less than the amount. The 2021 overview found no difference between steady cardio and high-intensity interval training (HIIT) for weight, fat or visceral fat when both used the same amount of energy. ACSM's 2024 statement also says HIIT doesn't appear to beat moderate-to-vigorous activity for body weight, and that the evidence doesn't show any single type of activity is better than others for losing weight.
• Walking counts. The same statement says lighter activity may work too, as long as you do enough of it. Brisk walking (you can talk, but not sing) is the easiest way for most people to add minutes.
• It builds fitness. In the 2012 trial, cardio improved aerobic fitness nearly three times as much as lifting did.

What lifting does well

• It protects muscle while you diet. In a 2008 study, 94 premenopausal women with overweight followed a diet until they reached a normal BMI, and each did lifting, cardio or no exercise. Only the lifting group kept its fat-free mass (muscle, bone, water and organs). The cardio and no-exercise groups lost some.
• It may help protect your resting energy use. In the same study, the calories the women burned at rest fell in the cardio and no-exercise groups but not in the lifting group.
• It lowers body fat even without weight loss. A 2022 analysis of 54 trials in healthy adults found that lifting for at least four weeks, compared with no exercise, lowered body fat percentage by about 1.5 points and fat mass by about 0.55 kg (1.2 lb) on average, and reduced visceral fat. The results didn't differ between men and women.

ACSM's 2009 position stand says resistance training "does not enhance weight loss but may increase fat-free mass," and adds that it may increase fat loss and is linked to lower health risk. That's the honest trade-off. Lifting isn't a shortcut to burning lots of extra calories, and in the 2012 trial the lifting group didn't lose weight. Its job during a diet is to make sure more of what you lose comes from fat.

Worried about getting bulky? After eight months of lifting three days a week, the 2012 lifting group gained about 1.1 kg (2.4 lb) of lean mass on average. That's real muscle, but a small amount spread across the whole body.

So which should you choose?

Both, with lifting as the base and cardio built on top. Food and movement can both create a deficit, but only lifting reliably protects your muscle while you do it. In practice:

1. Lift 2 or 3 days a week. Full-body sessions work well, with sets that finish 1 to 3 reps short of failure. Our gym workout plan for women has a 4-day split and a 3-day option.
2. Build toward at least 150 minutes a week of moderate activity. Brisk walks, cycling, swimming and classes all count.
3. Eat a little less than you burn. A modest deficit, not a crash diet.

A sample week that mixes both

Each strength session takes about 40 to 45 minutes. Keep the same exercises for 3 or 4 weeks, adding reps or weight when you can.

That's three strength sessions and 150 to 165 minutes of cardio and walking. For the exercises, sets and reps in each strength day, plus a 4-week progression, see our workout plan to lose weight for women.

• Short on time? In our view, the best two-hour week is two full-body strength sessions plus a daily walk.
• Too tired to lift well? Cut the cardio first. Your strength sessions are what protect your muscle.
• New to all of it? For the first two weeks, do 2 sets of each exercise and stop well short of failure. Add the third strength day and the longer cardio once the routine feels manageable.

If you'd rather not build the week yourself, HerShape builds a weekly workout plan around your goal, equipment and schedule, and adapts it to your cycle phase.

How to tell if it's working

The 2012 trial shows why the scale alone can mislead you, especially if you lift. Track three things:

• Your weekly average weight. Weigh at the same time a few mornings a week and compare averages, not single days. Your weight can rise for a few days before your period, mostly from water and what's in your gut, so compare the same week of your cycle from month to month. Our guide to weight gain before your period explains why.
• Your waist. Measure every 2 to 4 weeks, at the same spot.
• Your lifts. Write down your weights and reps. If they hold steady or rise while your weight trends down, that's a good sign you're keeping muscle.

Give any change at least a few weeks before you judge it.

When to check with a doctor

Talk to a doctor before starting a new program if you have a heart, lung or joint condition, high blood pressure or diabetes, if you're pregnant or postpartum, or if you've had an eating disorder or a difficult relationship with food. Stop exercising and get medical help right away for chest pain, fainting or severe shortness of breath. And if your periods stop or become irregular after you start training harder or eating less, see your doctor or gynecologist.

The bottom line

Cardio is better at moving the scale, lifting is better at protecting muscle, and doing both gives the best change in body composition. Exercise on its own moves the scale less than most people expect, so pair it with a modest deficit. Lift two or three days a week, walk or do cardio you enjoy on most other days, and judge progress by your weekly average, your waist and your lifts.

Sources

• Journal of Applied Physiology (2012): Effects of aerobic and/or resistance training on body mass and fat mass in overweight or obese adults
• Obesity Reviews (2021): Effect of exercise training on weight loss, body composition changes, and weight maintenance in adults with overweight or obesity: An overview of 12 systematic reviews and 149 studies
• Sports Medicine (2022): The Effect of Resistance Training in Healthy Adults on Body Fat Percentage, Fat Mass and Visceral Fat: A Systematic Review and Meta-Analysis
• Obesity (2008): Resistance training conserves fat-free mass and resting energy expenditure following weight loss
• Medicine & Science in Sports & Exercise (2009): American College of Sports Medicine Position Stand. Appropriate physical activity intervention strategies for weight loss and prevention of weight regain for adults
• Medicine & Science in Sports & Exercise (2024): Physical Activity and Excess Body Weight and Adiposity for Adults. American College of Sports Medicine Consensus Statement