If your goal is fat loss, the gym might matter just as much as your diet—and according to experts, lifting heavy weights could give you a major advantage over cardio alone.
In a recent breakdown, PhD nutrition expert Layne Norton explained why resistance training is often more effective for changing body composition than steady-state cardio. “Three reasons why weightlifting [beats] cardio for fat loss,” he says, are that it helps you lose more fat, preserve lean muscle, and reduce the chances of regaining body fat later on.
The Difference Between Dragging Through Your Day And Feeling Great On Your Feet? These Arch Support Insoles
Benefits of Heavy Lifting For Fat Loss
He points to a controlled study where participants followed a 500-calorie daily deficit over five months. The groups were split into no exercise, aerobic training (150–250 minutes per week), and resistance training two to three times per week. Protein intake was also matched across all groups.
Interestingly, total weight loss was similar across the board: the non-exercise group lost about 8.5 kilograms, the resistance training group lost 7.7 kilograms, and the cardio group lost around 9 kilograms. But Norton says the real story isn’t just the number on the scale—it’s what that weight actually consisted of.
The resistance training group experienced a powerful “recomposition” effect. “They actually gained lean mass in addition to losing fat mass,” he explains. In fact, they lost 8.9 kilograms of fat while building muscle at the same time, meaning their bodies became leaner even if total weight loss looked slightly lower.
By comparison, the non-exercise group lost significantly more muscle along with fat—about 2.9 kilograms of lean mass—while only 5.8 kilograms of that loss came from fat. The cardio group preserved more muscle than the sedentary group but still didn’t match the muscle-building benefits of lifting.
The bottom line
So what does this mean for weight loss? According to Norton, resistance training has a key metabolic advantage. Muscle tissue is more metabolically active than fat, meaning the more lean mass you have, the more calories your body burns even at rest.
He emphasizes that this doesn’t mean cardio is useless. In fact, combining resistance training with cardio often leads to the best overall results. But if you had to choose just one method for improving body composition, he says lifting weights still comes out on top.
The takeaway: the scale only tells part of the story—but lifting heavy weights may help you burn more fat, preserve muscle, and keep your metabolism working in your favor long after your workout ends.
