Macronutrient considerations for bodybuilders

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Macronutrient considerations for the sport of bodybuilding.

Lambert CP, LL, WJ.

Sports Med. 2004;34(5):317-27.

Participants in the sport of bodybuilding are judged by appearance

rather than performance. In this respect, increased muscle size and

definition are critical elements of success. The purpose of this

review is to evaluate the literature and provide recommendations

regarding macronutrient intake during both 'off-season' and 'pre-

contest' phases.

Body builders attempt to increase muscle mass during the off-season

(no competitive events), which may be the great majority of the year.

During the off-season, it is advantageous for the bodybuilder to be

in positive energy balance so that extra energy is available for

muscle anabolism. Additionally, during the off-season, adequate

protein must be available to provide amino acids for protein

synthesis. For 6-12 weeks prior to competition, body builders attempt

to retain muscle mass and reduce body fat to very low levels. During

the pre-contest phase, the bodybuilder should be in negative energy

balance so that body fat can be oxidised. Furthermore, during the pre-

contest phase, protein intake must be adequate to maintain muscle

mass.

There is evidence that a relatively high protein intake

(approximately 30% of energy intake) will reduce lean mass loss

relative to a lower protein intake (approximately 15% of energy

intake) during energy restriction. The higher protein intake will

also provide a relatively large thermic effect that may aid in

reducing body fat. In both the off-season and pre-contest phases,

adequate dietary carbohydrate should be ingested (55-60% of total

energy intake) so that training intensity can be maintained. Excess

dietary saturated fat can exacerbate coronary artery disease;

however, low-fat diets result in a reduction in circulating

testosterone.

Thus, we suggest dietary fats comprise 15-20% of the body builders'

off-season and pre-contest diets.Consumption of protein/amino acids

and carbohydrate immediately before and after training sessions may

augment protein synthesis, muscle glycogen resynthesis and reduce

protein degradation.

The optimal rate of carbohydrate ingested immediately after a

training session should be 1.2 g/kg/hour at 30-minute intervals for 4

hours and the carbohydrate should be of high glycaemic index. In

summary, the composition of diets for body builders should be 55-60%

carbohydrate, 25-30% protein and 15-20% of fat, for both the off-

season and pre-contest phases. During the off-season the diet should

be slightly hyperenergetic (approximately 15% increase in energy

intake) and during the pre-contest phase the diet should be

hypoenergetic (approximately 15% decrease in energy intake).

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Carruthers

Wakefield, UK