Table 4.
Effect of adaptation (5–10 days) to high-fat low-carbohydrate diet followed by carbohydrate restoration in trained individuals
| Participant characteristics | LCHF adaptation protocol | CHO restoration | Performance protocol | Nutritional status/strategies for performance | Performance advantage with LCHF adaptation + CHO restoration |
|---|---|---|---|---|---|
| Well-trained cyclists/triathletes [45] (n = 8 M) Crossover design |
5 days LCHF-adapt (fat = 68 % E; CHO = 18 % E, 2.5 g/kg BM) or HC (CHO = 74 % E, 9.6 g/kg BM CHO) |
1 day rest + high CHO (CHO = 75 % E, 10 g/kg BM) |
Cycling 120 min at 70 % VO2max + ~30 min TT (time to complete 7 J/kg BM) |
Fasted + no CHO intake during exercise | Perhaps for individuals Two participants performed badly on HC trial, probably because of hypoglycemia. Plasma glucose better maintained on LCHF-adapt trial. TT not significantly different between trials: 30.73 ± 1.12 vs. 34.17 ± 2.62 min for LCHF and HC trial. However, mean difference in TT = 8 % enhancement with LCHF trial (p = 0.21, NS; 95 % CI –6 to 21). |
| Well-trained cyclists and triathletes [41] (n = 8 M) Crossover design |
5 days LCHF-adapt (fat = 68 % E; CHO = 18 % E, 2.5 g/kg BM) or HC (CHO = 70 % E, 9.3 g/kg BM CHO) |
1 day rest + high CHO (CHO = 75 % E, 10 g/kg BM) |
Cycling 120 min at 70 % VO2max + ~30 min TT (time to complete 7 J/kg BM) |
CHO intake 2 h before exercise (2 g/kg BM) and during exercise (0.8 g/kg/h) | No Plasma glucose maintained in both trials due to CHO intake during exercise. Difference in TT between trials was trivial: LCHF-adapt = 25.53 ± 0.67 min; HC = 25.45 ± 0.96 min (p = 0.86, NS). Mean difference in TT = 0.7 % impairment with LCHF-adapt trial (95 % CI –1.7 to 0.4) |
| Highly-trained cyclists and triathletes [42] (n = 7 M) Crossover design |
6 days LCHF-adapt (fat = 69 % E CHO = 16 % E, 2.5 g/kg BM) or HC (CHO = 75 % E, 11 g/kg BM) |
1 day rest + high CHO (CHO = 75 % E, 11 g/kg BM) |
Cycling 240 min at 65 % VO2max + 60 min TT (distance in 1 h) |
CHO intake before exercise (3 g/kg BM) and during exercise (1.3 g/kg/h) | No or perhaps for individuals TT performance NS between trials: 44.25 ± 0.9 vs. 42.1 ± 1.2 km for LCHF-adapt and HC trial. However, mean difference in TT performance = 4 % enhancement with LCHF-adapt (p = 0.11, NS) (95 % CI –3 to 11) |
| Highly-trained cyclists and triathletes [43] (n = 7 M) Crossover design |
5 days LCHF-adapt (fat = 69 % E CHO = 16 % E, 2.5 g/kg BM) or HC (CHO = 75 % E, 11 g/kg BM) |
1 day rest + high CHO (CHO = 75 % E, 11 g/kg BM) |
Cycling 240 min at 65 % VO2max + 60 min TT (distance in 1 h) |
CHO intake before exercise (3 g/kg BM) and during exercise (1.3 g/kg/h) | No Additional six subjects undertaken to test for Type 1 error in previous study [42]. TT performance NS between trials: 42.92 ± 1.46 vs. 42.94 ± 1.41 km for LCHF-adapt and HC trial (p = 0.98). Performance difference = 0.02 km or 0.1 % |
| Trained cyclists and triathletes [44] (n = 5 M) Crossover design |
10 days LCHF-adapt (fat = 65 % E, CHO = 15 % E, 1.6 g/kg BM) or HC (CHO = 53 % E, 5.8 g/kg BM) |
3 days high CHO (CHO = 65 % E, 7 g/kg BM) + 1 day rest |
Cycling 150-min cycling at 70 % VO2max + 20-km (~30 min) TT |
MCT intake 1 h before event (~14 g); MCT (0.3 g/kg/h) and CHO (0.8 g/kg/h) during exercise | Yes Difference in TT performance = 4 % enhancement with LCHF-adapt: 29.35 ± 1.25 vs. 30.68 ± 1.55 min for LCHF-adapt and HC (p < 0.05) |
| Well-trained cyclists [36] (n = 7 M) Crossover design |
11.5 days LCHF-adapt (~2.4 g/kg, 15 % CHO; 66 % fat) or HC (CHO = ~8.6 g/kg, 70 % E) |
2.5 days high CHO (6.8 g/kg BM) | Cycling 5-h protocol including 15-min TT + 100-km TT |
HC: High-CHO pre-event meal Both: 0.8 g/kg/h CHO during exercise |
Perhaps—submaximal intensity exercise No—higher-intensity exercise Relative to baseline testing: HC trial showed small NS decrease in performance of both 15-min TT and 100-km TT. LCHF-adapt showed no change in 15-min TT but small NS enhancement of 100-km TT |
| Well-trained cyclists [1] (n = 8 M) Crossover design |
6 days LCHF-adapt (fat = 68 % E CHO = 17 % E, 1.8 g/kg BM) or HC (CHO = 68 % E, 7.5 g/kg BM) |
1 day rest + high CHO (8–10 g/kg) | Cycling 100 km TT, including 4 × 4-km sprints + 5 × 1-km sprints |
CHO consumed during ride | No—in fact, performance enhancement of 1-km sprints Differences between 100-km TT performances: NS (156 min 54 s vs. 153 min 10 s for LCHF-adapt vs. HC). Difference between power output during 4-km sprints: NS. However, power during 1-km sprints (undertaken at >90 % PPO) was significantly reduced in LCHF-adapt trial |
All values are mean ± standard error of the mean
BM body mass, CHO carbohydrate, CI confidence interval, E energy, HC high carbohydrate, LCHF low-carbohydrate high-fat diet, M male, MCT medium-chain triglyceride, NS not significantly different, PPO peak power output, TT time trial, VO2max maximal oxygen uptake