A Five-Week Periodized Carbohydrate Diet Does Not Improve Maximal Lactate Steady-State Exercise Capacity and Substrate Oxidation in Well-Trained Cyclists compared to a High-Carbohydrate Diet.
Study Goal
The researchers aimed to compare the effects of a periodized carbohydrate feeding strategy versus a high-carbohydrate diet on endurance training adaptations in well-trained cyclists.
Results Summary
Both groups showed improvements in maximal lactate steady state (MLSS) and body composition (increased muscle mass, decreased body fat), but no significant differences were found between the two dietary strategies in any measured outcomes.
Population
Well-trained cyclists (VO2peak = 70.8 ± 6.5 mL·kg-1·min-1).
Effective Dosage
Not specified (only described as "high-carbohydrate diet" and "periodized carbohydrate feeding").
Duration
5 weeks.
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
periodized carbohydrate feeding strategy | no change | measured outcomes | well-trained cyclists | - | did not elicit superior results | #1 |
periodized carbohydrate feeding strategy | no change | measured outcomes | well-trained cyclists | - | did not elicit superior results | #2 |
periodized carbohydrate feeding strategy | increase | maximal lactate steady state (MLSS) | well-trained cyclists | 244.1 ± 29.9 W to 253.2 ± 28.4 W | increased | #3 |
high-carbohydrate diet | increase | maximal lactate steady state (MLSS) | well-trained cyclists | 235.8 ± 21.4 W to 246.9 ± 16.7 W | increased | #4 |
periodized carbohydrate feeding strategy | no change | time to exhaustion at MLSS intensity | well-trained cyclists | - | not in | #5 |
high-carbohydrate diet | no change | time to exhaustion at MLSS intensity | well-trained cyclists | - | not in | #6 |
periodized carbohydrate feeding strategy | increase | percentage of muscle mass | well-trained cyclists | - | increased | #7 |
high-carbohydrate diet | increase | percentage of muscle mass | well-trained cyclists | - | increased | #8 |
periodized carbohydrate feeding strategy | decrease | percent body fat | well-trained cyclists | - | decreased | #9 |
high-carbohydrate diet | decrease | percent body fat | well-trained cyclists | - | decreased | #10 |
periodized carbohydrate feeding strategy | no change | carbohydrate oxidation | well-trained cyclists | - | no differences | #11 |
high-carbohydrate diet | no change | carbohydrate oxidation | well-trained cyclists | - | no differences | #12 |
periodized carbohydrate feeding strategy | no change | lipid oxidation | well-trained cyclists | - | no differences | #13 |
high-carbohydrate diet | no change | lipid oxidation | well-trained cyclists | - | no differences | #14 |
periodized carbohydrate feeding strategy | no change | heart rate | well-trained cyclists | - | no differences | #15 |
high-carbohydrate diet | no change | heart rate | well-trained cyclists | - | no differences | #16 |
periodized carbohydrate feeding strategy | no change | post-exercise lactate concentration | well-trained cyclists | - | no differences | #17 |
high-carbohydrate diet | no change | post-exercise lactate concentration | well-trained cyclists | - | no differences | #18 |
There is a growing interest in studies involving carbohydrate (CHO) manipulation and subsequent adaptations to endurance training. This study aimed to analyze whether a periodized carbohydrate feeding strategy based on a daily training session has any advantages compared to a high-carbohydrate diet in well-trained cyclists. Seventeen trained cyclists (VO2peak = 70.8 ± 6.5 mL·kg-1·min-1) were divided into two groups, a periodized (PCHO) group and a high-carbohydrate (HCHO) group. Both groups performed the same training sessions for five weeks. In the PCHO group, 13 training sessions were performed with low carbohydrate availability. In the HCHO group, all sessions were completed following previous carbohydrate intake to ensure high pre-exercise glycogen levels. In both groups, there was an increase in the maximal lactate steady state (MLSS) (PCHO: 244.1 ± 29.9 W to 253.2 ± 28.4 W; p = 0.008; HCHO: 235.8 ± 21.4 W to 246.9 ± 16.7 W; p = 0.012) but not in the time to exhaustion at MLSS intensity. Both groups increased the percentage of muscle mass (PCHO: p = 0.021; HCHO: p = 0.042) and decreased the percent body fat (PCHO: p = 0.021; HCHO: p = 0.012). We found no differences in carbohydrate or lipid oxidation, heart rate, and post-exercise lactate concentration. Periodizing the CHO intake in well-trained cyclists during a 5-week intervention did not elicit superior results to an energy intake-matched high-carbohydrate diet in any of the measured outcomes.