Let’s say you have set the caloric intake and protein intake based on your goals. The next step is to distribute the remaining calories into fat and carbs.

Protein always gets the most attention because it is necessary for protein synthesis and building muscles, but what about carb and fat intake? For endurance athletes, it is known to be ideal to eat a high-carb diet, however, what about a strength trainee? Low carb/high fat diet, high carb/low fat diet, or something in between, which one is optimal? This article will help shed some light and give some guidelines you can follow.



Each gram of dietary fat contains 9 calories and is mostly stored in adipose tissue. Fat is an essential nutrient that is vital for many functions in the body like; protection of vital organs, an energy source and reserve, thermal insulation, vitamin carrier and source, to name a few [1]. The function that fat has within the body when it comes to muscles is less known.

Diets comparing 20% and 40% of daily caloric intake coming from fat have found that 20% fat intake lowers testosterone levels in both males and females [2][3][4]. The drop in testosterone could be reduced by consuming adequate saturated fat [5]. That said, body composition and caloric deficit may be more important than fat intake for regulating testosterone levels. During starvation it has been shown that normal obese subjects don’t reduce testosterone levels [6]. Furthermore, a larger caloric deficit causes a higher drop in testosterone than a smaller deficit in normal weight subjects [7]. One may question how much attention this should be paid based on the belief that as long as testosterone is within a certain physiological range, then you shouldn’t lose sleep over it (unless you have super high physiological levels (steroid usage)). However, it has been shown that higher physiological testosterone levels are associated with more lean mass and less body fat than testosterone levels at the lower end of the physiological scale [8]. In sum, during severe caloric deficit, calories and body fat may have a higher impact on testosterone levels than fat intake. However, to be on the safe side, and since fat is an essential nutrient, it should not be forgotten.

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