Fuelling Exercise: Endurance vs Resistance

You might have heard of marathon runners carb loading before an event for optimal performance. Because carbs give us energy, right? In this article we summarise why you do not hear of bodybuilders and strength athletes using this protocol, and what might be more appropriate

Carb loading

The idea of feeding much higher than usual amounts of carbohydrate in the days leading up to an event such as a marathon is to increase muscle glycogen stores, so that there is more available to convert to glucose for energy to sustain long durations of aerobic exercise. Often, exercise is tapered or removed from a programme completely in the last couple of days to ‘fill’ the muscles as much as possible.

Very similar to techniques that bodybuilders employ to peak for a show so that they come in full and hard looking!

Resistance training

Perhaps the largest difference between resistance and endurance training is that they use different energy systems. For most people in the weight room, they are not utilising their aerobic energy system enough for glycogen stores to be the limiting factor to their performance. Therefore, carbohydrate loading before a session would be wasted.

An exception would be high volume sessions exceeding around 90 minutes, intra-workout carbs may have some benefit at this point. Dextose and maltodextrin are excellent options which are cheap and can be stacked with flavoured EAAs.

Above: MyProtein Dextose


What to do instead: food and supplements

A single high carbohydrate meal immediately before a session is unlikely to have much physiological benefit to anaerobic exercise. Instead, focus on taking in quality foods consistently over the course of days, weeks and months which fit your macronutritent needs.

Nevertheless, it is commonly believed that a balance of protein and carbohydrates, with minimal fat, is the best pre-workout meal for resistance athletes. The exact ratios and timing will depend on the individual and is worth experimenting with. Ideally, you want a meal that is easily digested and will not make you feel heavy and sluggish, but is still satiating enough to not be hungry in the gym. Something like chicken and rice cakes might be a suitable option.

While it is true that high fat and extremely low carb (keto style) dieting can eventually lead the body to use fats as energy in the muscle, this approach is more safe and effective for sedentary individuals than athletes, who have been shown to have no performance improvements, and may suffer from gastrointestinal discomfort as fats are more slowly digested than carbohydrates and slow down gastric emptying, the rate at which food can go from the stomach to the small intestine where nutrient absorption (including glucose) happens.

For weight training, caffeine and creatine monohydrate are great supplements to help with energy through a session.

Creatine supplementation increases phosphocreatine storage in the muscle so that ATP may be more easily resynthesized from ADP during short, high intensity exercise such as weightlifting. There is  evidence  that  creatine  supplementation  enhances  lean body   mass, muscle strength,   power, and maximal exercise  performance  in  specific  events  among  many individuals. (Racette, 2003).

Caffeine can be found in pre-workouts, some amino acid drinks and, of course, coffee and energy drinks. Again, assess your own tolerance, and cease use if you have any negative side effects or experience a ‘crash’ mid-session (especially a risk for longer sessions).


Racette, S. (2003). Creatine Supplementation and Athletic Performance. Journal of Orthopaedic & Sports Physical Therapy, 33(10), pp.615-621.

About the Author

Savannah Westerby, BSc Sport and Exercise Nutrition. IG:@savannahwesterby
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