Table 3.
Effect of up to 28 days of adaptation to high-fat low carbohydrate diet on performance of trained individuals
| Athletes | LCHF adaptation protocol | Performance protocol | Nutritional status/strategies for performance | Performance advantage with LCHF |
|---|---|---|---|---|
| Moderately trained cyclists [33] (n = 7 F) Crossover design |
7 days LCHF (fat = 59 % E, CHO = 1.2 g/kg BM) HC (CHO = 6.4 g/kg BM) |
Cycling TTE at 80 % VO 2max |
3–4 h after meal, no CHO intake during exercise | No In fact, performance deteriorated with LCHF. Time to exhaustion reduced by 47 % on LCHF trial |
| Well-trained cyclists [34] (n = 5 M) Crossover design |
14 days LCHF (fat = 67 % E, CHO = 17 % Ea) HC (CHO = 74 % Ea) |
Cycling 30 s Wingate test + TTE at 90 % VO2max + TTE at 60 % VO 2max |
Overnight-fasted + no CHO intake during exercise | No: two higher intensity tests Yes: Submaximal cycling Time to exhaustion increased by 87 % on LCHF trial commenced with lower glycogen stores due to preceding exercise |
| Well-trained cyclists [35] (n = 16 M) Parallel-group design |
15 days LCHF (fat = 69 %E, CHO = 2.2 g/kg BM) HC (CHO = 5.5 g/kg BM) |
Cycling 150 min at 70 % VO 2max + 40 km TT Performance measured at t = 0, 5, 10, and 15 days |
MCT intake 1.5 h before event (~14 g) MCT (0.3 g/kg/h) and CHO (0.8 g/kg/h) during exercise |
No TT performance increased over time in both groups as a result of training protocol. Significant improvements seen in both groups by day 10, but no difference in mean improvement between groups. Important finding of study: adaptations achieved after only 5 days of high-fat diet |
| Well-trained cyclists [36] (n = 7 M) Crossover design |
14 days LCHF (fat = 66 % E, CHO = ~2.4 g/kg) HC (CHO = ~8.6 g/kg, 70 % CHO) |
Cycling 5 h including 15 min TT + 100 km TT |
LCHF = high-fat pre-event meal HC = high CHO pre-event meal Both: 0.8 g/kg/h CHO during ride |
Yes: submaximal intensity exercise No: higher-intensity exercise Relative to baseline: HC showed small NS decreases in performance of both 15 min TT and 100 km TT LCHF showed larger but NS decrease in performance of 15 min TT but small NS improvement in 100 km TT |
| Well-trained duathletes [37] (n = 11 M) Crossover design |
5 weeks LCHF (fat = 53 % E, CHO = ~3.6 g/kg) HC (CHO = ~6.9 g/kg, 68 % CHO) |
Cycling 40 min incremental protocol + 20 min TT @ ~89 % VO 2max Running (separate day) Outdoor 21 km TT |
LCHF = high-fat pre-event meal HC = high CHO pre-event meal Intake pre and during half marathon not stated |
No Self-selected work output similar for cycling TT in both dietary treatments (298 ± 6 vs. 297 ± 7 W, NS) for LCHF and HC, respectively. Half marathon time not different between trials (80 min 12 s ± 86 s vs. 80 min 24 s ± 82 s, NS) |
BM body mass, CHO carbohydrate, E energy F female, HC high-carbohydrate diet, LCHF low-carbohydrate high-fat diet, M male, MCT medium chain triglyceride, NS not significant, TT time trial, TTE time to exhaustion, VO 2 max maximal oxygen uptake
ag/kg intakes unavailable