Table 2.

Summary of studies of adaptation to ketogenic low-carbohydrate, high-fat diet on performance of trained individuals

Athletes and study design	LCHF adaptation protocol	Performance protocol	Nutritional status/strategies for performance	Performance advantage with LCHF
Pre 2006
Well-trained cyclists [30] (n = 5 M) Crossover design with order effect (control diet first)	7 days HC (57 % CHO) then 28 days LCHF (fat = 85 % E, CHO = <20 g/day)	Cycling; TTE at 60 % VO2max	Overnight-fasted + no CHO intake during exercise	No NS difference in TTE between trials (151 vs. 147 min for LCHF and HC). Group data skewed by one participant who increased time to fatigue by 156 % on LCHF trial (Fig. 1)
Post 2006
Moderately trained off-road cyclists [49] (n = 8 M) Crossover design	28 days HC (CHO = 50 % E) LCHF (fat = 70 % E, CHO = 15 %)? truly ketogenic	Cycling; VO2max test	Not stated	No Mixed results, with small increase in VO2max (56 vs. 59.2 ml/kg/min for HC and LCHF, p < 0.01) but reduction in maximum workload (350 vs. 362 W, p = 0.037). Small favorable change in body composition with LCHF (loss of ~1.8 kg with body fat loss from 14.9 to 11.0 % BM, p < 0.01)
Elite artistic gymnasts [50] (n = 8 M) Crossover design with order effect (control diet second)	30 days HC (CHO = 47 % E, 3.9 g/kg) then 30 days LCHF (fat = 55 % E, CHO <25 g/day) (note protein = 40 % E + added supplements)	Strength exercises: squat jump, countermovement jump, push-ups, reverse grip chin test, legs closed barrier maximum test	Not stated	No No change in strength measurements across either dietary phase—therefore, no impairment of performance measures with LCHF diet. Small favorable change in body composition with LCHF (loss of ~1.5 kg with body fat loss from 7.6 to 5.4 % BM)

BM body mass, CHO carbohydrate, E energy, HC high-carbohydrate diet, LCHF low-carbohydrate high-fat diet, M male, NS not significant, TTE time to exhaustion, VO ₂ max maximal oxygen uptake