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Cardio or Strength Training for Weight Loss?

JYL Balance ·
Cardio or Strength Training for Weight Loss?

The question comes up in every gym, and it is framed wrong. Cardio and resistance training do not serve the same purpose during weight loss: one widens the energy gap, the other protects your metabolic capital. The right answer is not "either/or" but "both, with different jobs".

What the Trial That Settled It Found

The randomised STRRIDE AT/RT trial followed 119 sedentary adults with overweight or obesity, assigned for eight months to one of three protocols: aerobic training alone, resistance training alone, or a combination of the two. The primary outcomes were total body mass, fat mass and lean body mass.

The result: the aerobic and combined groups reduced total body mass and fat mass more than resistance training alone, with no significant difference between them. For fat mass reduction at comparable volume, aerobic training emerges as the more effective mode.

But the trial did not stop there. On quality of life, only the resistance and combined groups significantly improved their physical component score, and only the combined group improved its mental component score. That matters, because long-term adherence depends heavily on how the work makes you feel.

Why Resistance Training Remains Essential

Cardio moves the scale down. Resistance training decides what moves down. A meta-analysis of thirty studies on preserving lean mass during weight loss found a moderate, significant effect for training combined with high protein compared with high protein alone.

This fits what we know about regain: less muscle means lower resting expenditure, and therefore more fertile ground for the yo-yo effect. In the short term, lifting "pays" little on the scale; in the medium term, it protects the result.

The Baseline: Official Guidelines

The WHO recommends that adults get at least 150 to 300 minutes of moderate-intensity endurance activity per week, or 75 to 150 minutes of vigorous activity, or an equivalent combination, plus muscle-strengthening activities working the major muscle groups at least twice a week. Since 2020, the requirement for bouts of at least ten minutes has been dropped: every period of movement counts.

For comparison, people who successfully keep weight off report substantially higher activity levels, on the order of an hour a day.

How to Split It in Practice

  • Two strength sessions a week, non-negotiable, covering the major muscle groups. That is the floor, not the target.
  • Everything else in endurance, in whatever form you will actually keep doing: brisk walking, cycling, swimming, rowing.
  • Count daily walking. It is often the largest modifiable share of expenditure, with no fatigue or recovery cost.
  • Do not turn exercise into compensation. One hard session does not "buy back" a week, and overestimating calories burned is the most common error.
  • Prioritise consistency over intensity in the early months: the best session is the one you will still be doing in six months.
  • Pick something you enjoy, even if it looks less efficient on paper. Adherence beats optimisation.
  • Seek medical advice before restarting if you have cardiovascular or joint conditions, or have been sedentary for a long time.

The Takeaway

Cardio is the tool for expenditure, resistance training the tool for preservation. Pitting them against each other means choosing between widening the deficit and protecting what will make it last. If you keep only one rule: two strength sessions a week, and as much walking as possible the rest of the time.

Sources

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