This week, we explore how athletes can best preserve muscle mass and strength whilst attempting to drop body fat.
As many athletes will be aware, large energy deficits come with an array of physiological, psychological and emotional compromises. Therefore, the magnitude of the energy deficit dictates KPI outcomes.
From a muscle centric view, a recent analysis by Murphy and Koehler (2021) investigated the calorie deficit thresholds in which changes in muscle mass and strength can be seen.
Although this review wasn’t conducted in elite athletes, the 7 studies and 282 participants analysed followed a weight training and nutrition programme that induced ~350-570kcal energy deficit/day.
Therefore, we can draw some conclusions. On average:
1) The overall effect of lifting weights combined with an energy deficit was negative for GAINS IN LEAN MASS when compared to those on a maintenance calorie intake.
2) The overall effect of lifting weights combined with an energy deficit for GAINS IN STRENGTH was positive, and the same as those on a maintenance calorie intake.
3) Strength gains were unaffected by an energy deficit despite maintenance or losses in lean mass. Most likely, strength gains occurred through neurological adaptations.
When further analysis was carried out, they found that:
1) A 500kcal deficit would result in no losses of lean mass. Therefore, if you’re looking to maintain lean mass whilst dropping body fat, keep the deficit <500kcal/day.
2) A 500kcal deficit would wipe out the potential gains in lean mass that could have been made if you were at calorie maintenance. Therefore, if your goal is to maximise lean mass gains, don’t be energy deficient.
3) A linear relation was seen between the magnitude of an energy deficit and lean mass loss (up until a certain point, theoretically).
One major limitation to this review is that they were unable to control for protein intake, which we know is absolutely essential for muscle protein synthesis and the accrual of new muscle tissue. Plus, I’d probably question the intensity of their weight training programmes too…
This study does however show a nice relationship between calorie intake and lean mass retention, but we could assume results would be the same or greater when protein intake is high.
That being said, a calorie deficit >500kcal/day isn’t ideal for all performance related outcomes. So keep your deficit small and manageable.