Cutting Carbs After PM HIIT Workouts Will Make You Cross the Finish Line Before Anyone Else: 3% Faster Time Trial, 9% More Power and Twice as Much Fat Mass Lost in 7 Days
|Don't be a fool. Simply eating no carbs in the PM is not going to yield the same results. It's all about timing it correctly with your workouts... workouts? Yes, bad news: you got to get off the couch, bro; workout daily: one light, one HIIT day.|
Now, the scientists go one better: In their latest study, Laurie-Anne Marquet and colleagues investigated the effect on an even shorter timescale - a timescale that is short enough to consider "sleeping low" as a possible pre-competition strategy... well, assuming that it would work its performance-enhancing magic within as little as the 7 days, during which the subjects' in Marquet's study followed the "no carbs after your workout" (="sleep low" | SL) prescription the researchers copied from their own previously discussed study.
Overall, 21 endurance-trained male cyclists (mind the typo about the # in the abstract of the original study, in case you read it; the summary says 11, not 21, which is the correct number) volunteered to participate in the study. All were healthy, aged between 18 and 40 years, and training at least 12 h/week, having at least 3 years of prior training. Their mean (±SD) age was 31.2 ± 7.1 years, their mean body mass was 71.1 ± 5.6 kg, their mean maximal oxygen consumption (VO2max) was 64.2 ± 6.0 mL/min/kg, and their mean maximal aerobic power (MAP, W) was 342 ± 38.3 W.
To isolate the effects of the dietary / carbohydrate modulating intervention, the subjects who trained
according to their habitual training program, initially (1st week) ate according to their usual dietary habits, documenting their food intake via a daily food diary. These diaries were then compared to the prescribed carbohydrate pattern in the 2nd week, which set their CHO intake at 6 g/kg per day.
|Figure 1: Graphical overview of the study design; CHO: carbohydrates; HIT: high‐intensity training session; LIT: light intensity training session; SL: Sleep‐Low; CON: Control; MAP: Maximal aerobic power (Marquet. 2016).|
|The study used pre-bed protein shakes, a strategy to build muscle.|
- the control group trained with a high CHO availability (control group, CON group, n = 9) with an even spread of CHO intake over the day and between training sessions,
- the "sleep low" (SL) group (n = 12 | mind the typo in the scientist' abstract) trained with a CHO intake that was periodized within the various days in a way that no CHO was consumed between the high-intensity interval training sessions (HIIT) held
|Figure 2: 20km cylcling times and mean power output in pre- and post-test (Marquet. 2016).|
|Table 1: Rating perception of effort (RPE) during the 20 km cycling time-trial every 5 km (Marquet. 2016).|
- no decrease in CHO oxidation in the SL group and
- no increase in FAT oxidation in the SL group
- no increased cellular damage in form of lipid oxidation, and
- no significant difference in the subjects' stress response (plasma catecholamines),
- Marquet, Laurie-Anne, et al. "Periodization of Carbohydrate Intake: Short-Term Effect on Performance." Nutrients 8.12 (2016): 755.
- Schoenfeld, Brad, et al. "Body composition changes associated with fasted versus non-fasted aerobic exercise." Journal of the International Society of Sports Nutrition 11.54 (2014). Previously discussed, here!