- Different types of exercise provide different benefits when dieting.
- Emphasis of cardio vs. resistance training is ultimately goal specific.
- Cardio helps increase calorie expenditure.
- Resistance training helps preserve lean body mass.
A common question that arises regarding dieting is “what’s better for fat loss, cardio or weights?”
Ideally, most people will be doing some mixture of both. They each have their own distinct benefits while dieting. However, which one is more focused on depends on the person in question.
Cardiovascular Training (Cardio)
Cardio generally consists of some sort of exertion that elevates one’s heart rate, and maintains that elevated rate for a period of time. Both the duration and the intensity of the activity can vary. For most intents and purposes, the cardio exercise of choice will depend on personal preference.
As expected, the primary benefit from cardio lies in the cardiovascular system itself. In particular, cardio strengthens the cardiovascular system and makes it more efficient, increasing fitness across several measures1.
In the context of fat loss, cardio is usually used to increase one’s calorie expenditure. Recall that in order for fat loss to occur, calorie expenditure must exceed calorie intake. Cardio can increase the expenditure side of the equation, thus assisting with fat loss.
Resistance training involves some sort of muscular exertion against an opposing force. This can consist of several possibilities, including bodyweight exercises, free weights, and machines. Like with cardio, resistance training is heavily influenced by individual preference, and many approaches are viable.
When dieting, the main benefit of resistance training is preserving lean body mass (LBM). In a calorie deficit, the body loses mass, both from fat stores as well as from LBM2. However, muscle contractile activity is one of the primary regulators of muscle protein synthesis and breakdown3. In other words, resistance training helps maintain the body’s muscle through continual use. This results in less LBM loss, and thus ensures most of the loss is from fat.
As a final note, resistance training is often touted for its “afterburn” effect on calorie expenditure. This is a phenomenon known as exercise post-activity oxygen consumption (EPOC), and involves an elevation of metabolism that continues after the activity has ceased. Unfortunately, the magnitude of EPOC tends to be overstated, and is modest enough4 that it should not be a major factor in choosing between weights and cardio.
Ideally, most people will do both cardio and resistance training as they lose weight. In a perfect world, it would be plenty of both.
However, one final consideration is fatigue. Any serious amount of exertion will require some time for rest and recovery. When in a calorie deficit, recovery tends to be impaired compared to energy maintenance or surplus. Therefore, it is generally a good idea to be prudent with activity, e.g. more is not always better.
You should emphasize the activities most aligned with your personal goals. For example, if your goals are appearance based, it would be wise to focus on resistance training as the core of your activity. Or, if you regularly participate in sports, emphasizing cardiovascular performance may be a wise idea.
- Braun LT. Exercise physiology and cardiovascular fitness. Nurs Clin North Am. 1991 Mar;26(1):135-47.
- Weinheimer EM, Sands LP, Campbell WW. A systematic review of the separate and combined effects of energy restriction and exercise on fat-free mass in middle-aged and older adults: implications for sarcopenic obesity. Nutr Rev. 2010 Jul;68(7):375-88. doi: 10.1111/j.1753-4887.2010.00298.x.
- Rennie MJ, Wackerhage H, Spangenburg EE, Booth FW. Control of the size of the human muscle mass. Annu Rev Physiol 2004;66:799–828.
- LaForgia J, Withers RT, Gore CJ. Effects of exercise intensity and duration on the excess post-exercise oxygen consumption. J Sports Sci. 2006 Dec;24(12):1247-64.