Cardio burns more calories during a workout and produces more total weight loss than lifting weights alone. But that answer only tells part of the story, because the number on the scale doesn’t distinguish between losing fat and losing muscle. When you factor in body composition, the case for weight training gets much stronger, and the best results come from doing both.
What the Scale Actually Shows
In a head-to-head trial of overweight adults, those assigned to aerobic training lost an average of 1.76 kg of body weight over the study period. The resistance training group lost just 0.83 kg. The group that combined both lost 1.63 kg, which was statistically no different from cardio alone. On fat mass specifically, the gap was even wider: the cardio group dropped 1.66 kg of fat, while the lifting group lost only 0.26 kg. Combining both yielded the largest fat loss at 2.44 kg, though this wasn’t statistically different from cardio alone.
Waist circumference told the same story. It shrank significantly in the cardio and combined groups but didn’t change in the resistance-only group. If your primary goal is seeing the scale move down as fast as possible, aerobic exercise has a clear edge.
Calories Burned During Exercise
Minute for minute, cardio and lifting are closer than most people think. In a controlled comparison of men exercising for 30 minutes, treadmill running at a moderate intensity burned about 9.5 calories per minute, cycling burned about 9.2, and weight training at 75% of max effort burned roughly 8.8. That’s a difference of less than one calorie per minute. High-intensity interval training on a resistance machine outpaced all three at 12.6 calories per minute, which shows that intensity matters more than the category of exercise.
The practical gap widens, though, because most people can sustain cardio for longer stretches than lifting. A 45-minute run is straightforward. A 45-minute lifting session includes rest periods between sets where calorie burn drops substantially. Over a full workout, cardio typically accumulates more total calories burned for this reason alone.
The Afterburn Effect
Lifting does have one metabolic advantage: it creates a larger “afterburn,” the elevated calorie expenditure your body sustains after you stop exercising. In a study of fit women, resting metabolic rate was still about 12% higher 14 hours after a resistance training session compared to baseline. High-intensity interval training on a treadmill also elevated metabolism, but the resistance training session produced a greater bump. Neither type of exercise kept metabolism elevated past 24 hours.
This afterburn is real, but it’s often overstated in fitness marketing. An 12% increase in resting metabolism for 14 hours translates to maybe 50 to 80 extra calories, roughly the equivalent of an apple. It helps at the margins, but it won’t overcome a large calorie gap on its own.
Why Muscle Preservation Changes the Equation
Here’s where weight training earns its keep. When you eat fewer calories than you burn, your body doesn’t just pull from fat stores. It also breaks down muscle. In a meta-analysis of adults dieting to lose weight, adding resistance training reduced muscle loss by 93.5% compared to dieting alone. Both groups lost similar amounts of total body weight and fat, but the lifting group held on to nearly all of their lean mass while the diet-only group lost a meaningful amount.
This matters for two reasons. First, muscle burns about 6 calories per pound per day at rest, while fat burns only about 2. Losing muscle during a diet gradually lowers your resting metabolism, making it harder to keep losing weight and easier to regain it. Second, muscle quality (how much force your muscles produce per unit of tissue) improved by about 21% in the group that lifted during their diet and declined by about 7.5% in those who didn’t. Preserving muscle isn’t just cosmetic. It affects how strong and functional you feel as you get leaner.
How Each Type Affects Hunger
Exercise doesn’t just burn calories. It also changes how hungry you feel afterward, and the two types do this differently. Both aerobic and resistance exercise suppress ghrelin, the hormone that drives hunger, during and shortly after a workout. But aerobic exercise has an additional effect: it raises levels of a satiety hormone called PYY, which helps you feel full. In one study, PYY concentrations were about 25% higher across an eight-hour period on the aerobic exercise day compared to the resistance exercise or rest days.
Resistance training suppressed ghrelin for a slightly longer window (about 90 minutes versus 45 minutes for cardio), but it didn’t boost the fullness signal the way cardio did. If overeating after workouts is a challenge for you, cardio may offer a slight appetite-regulation advantage.
How Much Exercise You Actually Need
The American College of Sports Medicine’s position on weight loss lays out specific thresholds. Getting 150 to 250 minutes per week of moderate-intensity activity (like brisk walking or easy jogging) is enough to prevent weight gain but produces only modest weight loss. To see clinically significant results, you need more than 250 minutes per week. For long-term weight loss and maintenance, the recommendation is 200 to 300 minutes weekly.
The ACSM’s position on resistance training is notably different: it does not enhance weight loss on its own, but it increases fat-free mass and promotes greater fat loss relative to the weight you do lose. In other words, lifting reshapes what your weight is made of, even when it doesn’t change the total number much.
The Case for Doing Both
If you only have time for one type of exercise and your sole goal is losing the most weight, cardio wins. It burns more total calories per session, produces larger drops in body weight and fat mass, and has a stronger effect on appetite hormones that help control overeating.
But if your goal is to look and feel leaner (not just lighter), adding resistance training changes the outcome significantly. Lifting preserves the muscle that keeps your metabolism higher, improves your body composition so you look more toned at the same weight, and protects your strength during a calorie deficit. In the studies that combined both, fat loss was the highest of any group, even though total weight loss wasn’t much different from cardio alone. That gap between weight lost and fat lost is all muscle that was saved.
For most people, the practical sweet spot is three to four days of moderate cardio for calorie burning and appetite control, plus two to three days of resistance training to protect muscle and metabolism. The cardio does the heavy lifting on the calorie deficit. The weights make sure the weight you lose is the weight you actually want to lose.