November 6, 2026

Resistance, Aerobic, or Both? What Trials Show About the Best Exercise for Sarcopenic Obesity

By Dr. Zakira Naureen, Associate Professor, University of Nizwa
Exercise Body Composition Young Adults

In Simple Terms

  • If I only walk or jog to lose weight, am I quietly losing muscle along with the fat?
  • Do I really need to lift weights, or is cardio enough to fix low muscle and extra body fat?
  • Is it worth doing both, and what did people actually gain when they did?
  • How much of this research was done on people my age, and what is still unknown?

People who want to lose body fat are usually told to move more, but "move more" hides an important choice. A brisk run, a weights session, and a mixed class all burn calories, yet they send very different signals to muscle. For someone with sarcopenic obesity, which means too little muscle for the amount of body fat carried, the type of exercise may matter as much as the amount. This article reviews what randomized trials and pooled analyses show about aerobic training, resistance training, and combined programs, and where the evidence is thin.

The mechanism: why different exercise sends different signals to muscle

Muscle mass is the running balance between building new protein and breaking old protein down. Resistance exercise places high tension on muscle fibers, and that tension is the main trigger for building new muscle protein. Aerobic exercise mainly trains the heart, lungs, and the energy machinery inside cells, and it places far less mechanical load on muscle. During weight loss, the body also tends to give up some muscle along with fat, and the question is which type of exercise best offsets that.

Excess body fat adds a complication. As we describe in our post on insulin resistance and muscle protein synthesis, muscle in people carrying extra fat can respond less vigorously to the usual building signals. If that is true, an exercise type that provides a weak building signal may be especially unlikely to protect muscle in this group.

Evidence 1: a trial that measured muscle building directly

The most direct evidence comes from a trial by Colleluori and colleagues in Cell Metabolism (2019), a muscle metabolism substudy of a larger randomized trial in older adults with obesity (aged 65 and over). Forty seven people completed six months in one of four groups: no intervention, or weight management with aerobic exercise, resistance exercise, or both. The three exercise groups lost a similar amount of body weight, about 9 percent.

Lean mass told the story. It fell by 2.8 kg (about 5 percent) in the aerobic group, 1.1 kg (about 2 percent) in the resistance group, and 1.7 kg (about 3 percent) in the combined group, while the no intervention group gained 0.4 kg. Thigh muscle volume followed the same pattern. Strength rose by about 16 percent with resistance and 17 percent with combined training, but only about 3 percent with aerobic training. Muscle protein synthesis rose by 114 percent in the resistance group and 45 percent in the combined group, compared with a smaller shift in the aerobic group (from 0.087 to 0.108 percent per hour). The resistance group's rise in muscle protein synthesis was significantly greater than the aerobic group's. Combined training did give the largest gain in a physical performance test (5.6 points versus 3.8 for the other two exercise groups). The authors concluded that combined exercise was superior to either type alone for muscle protein synthesis and muscle quality. Note, however, that the resistance group actually showed the bigger rise in muscle protein synthesis and the smallest lean mass loss, so the clearest added value of combining the two in this study was physical performance and fitness.

This was a small study in older adults, so it shows the mechanism clearly but cannot tell us how young adults would respond.

Evidence 2: a network meta-analysis in people with sarcopenic obesity

Qiu and colleagues (Frontiers in Nutrition, 2025) pooled 14 controlled trials (all but one randomized) with 955 adults aged 60 or older who had sarcopenic obesity. They compared aerobic training, resistance training, combined aerobic plus resistance training, and multicomponent training (three or more types, such as strength, aerobic, balance, and flexibility) against control groups. Trials that added supplements, drugs, or calorie restriction were excluded, so these results reflect exercise alone.

Multicomponent training ranked best for body composition and walking speed. Compared with control, it lowered body fat percentage by a mean of 6.37 points and was the only approach with a clear gain in fat free mass (mean difference 5.21, 95 percent CI 1.51 to 8.91). Resistance training alone lowered body fat percentage by 1.85 points, ranked highest for the 30 second chair stand test, and was essentially tied with multicomponent training for grip strength. Combined training lowered body fat percentage by 2.08 points and improved walking speed, though less than multicomponent training. Aerobic training alone did not differ significantly from control on body fat percentage.

A takeaway worth noting is that the "best" program depended on the goal. If the goal is to cut fat percentage and improve walking speed, broader programs came out ahead. If the goal is strength and chair stand performance, resistance training performed as well as or better than the broader programs.

Evidence 3: resistance training in people with overweight and obesity generally

Lopez and colleagues (Medicine and Science in Sports and Exercise, 2022) pooled 65 randomized trials with 2,537 adults who were overweight or had obesity. Resistance based programs reduced fat mass by 1.6 kg and increased lean mass by 0.8 kg on average. Two findings are especially relevant to young adults. First, younger adults gained more lean mass than older adults. Second, neither the amount of resistance training nor adding aerobic exercise was linked to the size of the change, which suggests that starting a consistent program may matter more than perfecting it. Our post on resistance training volume explores that dose question in more detail.

The same analysis reported that programs combining resistance exercise with calorie restriction resulted in significant reductions in lean mass (the abstract does not say what that was compared against). This is a reminder that resistance training does not make dieting risk free for muscle, since cutting calories can still pull lean tissue down.

Evidence 4: exercise added to calorie restriction

Xie and colleagues (Frontiers in Nutrition, 2025) ran a network meta-analysis of 62 randomized trials with 4,429 healthy adults who reduced calories, with or without different kinds and intensities of exercise. Calorie restriction alone was the only arm with a statistically significant loss of lean body mass compared with control. None of the arms that added exercise showed a significant change. The authors concluded that moderate or low intensity resistance or aerobic exercise alongside a calorie deficit optimizes fat loss while preserving lean mass. This supports the idea that some exercise is better than none during weight loss. We use this paper only for its overall direction, because its results are standardized effect sizes with wide confidence intervals, some numbers in its abstract appear to be duplicated or mislabeled, and all included studies had unclear blinding.

What this means in practice

  • If you are cutting calories or using weight loss medication, treat resistance training as the protective piece. Aerobic exercise alone was linked to the largest lean mass loss in the one trial that compared the types directly, which echoes what we discuss in our posts on protein during a calorie deficit and GLP-1 drugs and lean mass.
  • Do not drop cardio. Combined and multicomponent programs improved fitness, walking speed, and physical performance in ways resistance training alone did not always match, and they matter for heart and metabolic health.
  • Start with what you can sustain. The pooled data found no clear advantage from higher resistance training doses, so a few well performed sessions each week is a reasonable beginning. Our strength training basics and complete guide for young adults explain how to get started.
  • Pair training with adequate protein and sleep. Exercise sends the signal to build muscle, but the raw materials and recovery still have to be there.

Limitations and open questions

The strongest evidence in people who actually have sarcopenic obesity comes from older adults, mostly women, and the network meta-analysis included only 14 trials. It found only two trials of aerobic training alone, with 35 participants, so the aerobic estimates are weak. Trials used different diagnostic standards for sarcopenia, many comparisons were indirect, and heterogeneity was high across outcomes. The head to head trial that measured muscle protein synthesis had under fifty completers. Body scans measure lean mass, which includes water and organs, so small changes may not reflect functional muscle. We also did not locate a randomized trial comparing exercise types in young adults with sarcopenic obesity, and the findings in older adults may not carry over directly. Results in Gulf populations, where heat, daytime schedules, and gym access shape how people exercise, are largely unstudied. That gap is one reason our research project is screening young Omani adults and examining how precision nutrition can be paired with exercise.

This post is for general education and is not medical advice. Please speak with a qualified healthcare provider before starting a new exercise program, especially if you have a medical condition, are returning from injury, or take medication.

References

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