Cardio vs weights for fat loss: what each one did in the trials, and why most plans use both

Most people ask this as if one has to win. The trials that put cardio and lifting side by side found something more useful: each did a different job, and doing both did both jobs. What follows is what each study measured, in the words it measured it, and how to put the two in one week.

Two limits first. Neither kind of training replaces the food side, which is on calories and protein; the full fat-loss list is how to lose body fat. And this page is about which to do, not which order to do them in a session; that's cardio and lifting, summarised in the FAQ below.

1. The head-to-head trial

The clearest comparison is a 2012 randomized trial of 119 sedentary, overweight or obese adults, who trained for eight months in one of three ways.¹

The group that did both spent twice the time and didn't lose significantly more fat or weight than the cardio group. The authors' reading, for middle-aged adults with overweight or obesity: cardio is the mode of exercise to choose for reducing fat mass and body mass, and a program that includes lifting is needed to increase lean mass.¹

2. The longer trials in obesity say the same

A 2021 network meta-analysis pooled 32 randomized trials with 4,774 participants with obesity, each lasting at least six months. Cardio ranked first for body weight, BMI and waist size; cardio and lifting combined ranked first for fat mass; and combined training and lifting ranked level at the top for fat-free mass. The authors rated the certainty of the evidence low to moderate.² In their conclusions, lifting in these trials reduced fat mass and improved fat-free mass, and adding it to cardio gave an extra benefit for both.²

3. Lifting on its own still takes fat off

Lifting losing the head-to-head isn't the same as lifting doing nothing for fat. A 2022 review of 58 studies in healthy adults, 54 of them pooled, compared full-body resistance training, for at least four weeks, with not exercising at all. Lifting reduced body fat percentage and body fat mass compared with the control groups.³ The American College of Sports Medicine's position stand puts the trade this way: resistance training doesn't add to the weight you lose, but it may increase fat-free mass and the loss of fat mass.⁴ That's why the scale undersells lifting: it counts the muscle you keep or add along with the fat. More on that: body recomposition.

4. During a calorie cut, lifting is what keeps the muscle

In the head-to-head trial, lifting was what added lean mass; during a calorie cut, it's what holds on to it. In a 2018 analysis of six trials in older adults with obesity, lifting three times a week during a calorie cut prevented almost all of the lean mass that the cut alone cost, and the fat loss was not significantly different with or without it.⁵ The fat came off from the calorie cut; the lifting kept the muscle. The food side is on calories and protein.

5. Which cardio

The kind matters less than people think. A 2017 meta-analysis of 31 studies found interval and steady cardio about even for body fat.⁶ The comparison is on HIIT vs steady-state cardio; the easiest kind to keep up is daily walking; and whether to do it fasted is on fasted cardio.

6. Both in one week

The World Health Organization's guideline for adults already asks for both: 150 to 300 minutes of moderate activity a week, or 75 to 150 of vigorous, plus muscle-strengthening activities that involve all major muscle groups on two or more days a week.⁷ A practical week that covers both, not a protocol from a trial:

New to all of it? Start with two lifting days and half the cardio, and build from there: how much cardio per week and how to start lifting weights.

Common questions

Is cardio or weights better for weight loss?

For the number on the scale, cardio moved it more: in the eight-month trial, cardio reduced body weight more than lifting, and in the longer trials in obesity, cardio ranked first for body weight.^1,2 But the scale counts muscle too, and lifting is what added lean mass. If what you want is less fat and the same or more muscle, the trials point to both.

Is cardio or weights better for fat loss?

In the head-to-head trial, cardio reduced fat mass more than lifting; in the longer trials, cardio and lifting combined ranked first for fat mass.^1,2 Lifting alone still reduced body fat compared with not exercising.³

Should I do cardio or weights first to lose fat?

For body fat, the order didn't show a difference. A 2018 meta-analysis of 10 studies of healthy adults, each lasting five weeks or more, found no effect of exercise order on body fat percentage; lifting before cardio did give more lower-body dynamic strength.⁸ So if strength matters to you, lift first. The rest of the order question, including same day or separate days: cardio and lifting.

Can you lose fat by lifting weights only?

Yes: in the 2022 meta-analysis, lifting alone reduced body fat percentage and fat mass compared with not exercising.³ In the head-to-head trial it reduced fat mass less than cardio did.¹ Either way, the calorie side does most of the work: how to lose body fat.

Cardio or weights to lose belly fat?

In the longer trials in obesity, cardio ranked first for waist size.² Whether training one area takes fat off that area is a different question, with its own trials: how to lose belly fat.

Is it different for women?

Not in the analysis that tested it: in the 2022 review of lifting, sex didn't significantly change its effect on body fat percentage or fat mass.³ And women were most of the head-to-head trial: of the 119 adults, 68 were women.¹ Lifting for women specifically: strength training for women.

If you'd rather have someone build the week

Knowing you need both is the easy part; fitting both into a real week, and changing the mix when the trend stalls, is the hard part. Coaching is the version where your workouts live in Trainerize, built around the days you actually have, and someone reads your weigh-ins, photos and logged workouts every week and adjusts the plan. Fat loss coaching explains how that works, and apply is the first step. Otherwise: put two lifting days and two cardio sessions in your calendar this week.