|You could use this exercise to deplete your glycogen levels before "cardio".|
If you take a look at the data in Figure 1, you will notice that the rate of fatty acid oxidation was significantly higher both during (EXERCISE) and after the workout (EPOC).
|Figure 1: VO2 as a marker of fatty acid oxidation during (EXERCISE) and after (EPOC = excess post-exercise oxygen consumption) in 5 physically active males in response to submaximal exercise on high- vs. low-CHO diets (Ferreira. 2016).|
Don't be fooled - Increased fatty acid oxidation does not necessarily translate to increased fat loss! If this is not your first SuppVersity article, you probably know that already. For the occasional newcomer, however, it is vital to understand that the lipids you burn during and after your workouts (a) won't necessarily come from your belly and (b) can be easily restored after the workout even if they came from your more or less abundant adipose energy stores.Before we get deeper into the discussion of the implications of the results, however, it is imperative to take a look at the methodology of the experiment the scientists from Vitória de Santo Antão, the Universidade de São Paulo, and the Universidade Federal de Lavras have conducted last year.
Now these "alterations" comprised (a) a glycogen-depletion exercise protocol 48 h before each experimental session. As Ferreira et al. point out, "[t]his protocol consisted of a 90-min cycling at 50% of the difference between LT1 and LT2, followed by 6×1 min exercise bouts at 125% of V̇O2 peak; 1 min recovery was allowed between effort sets" (Ferreira. 2016), and (b) different baseline diets (see light-blue box for more information about the diet - will be updated, if possible).
"[A]fter receiving verbal and written explanations, and signing an informed consent, 5 physically active males (age 31.0±7.7 years, height 180.2±4.3 cm, body mass 77.0±7.7 kg, body fat 13.3±2.9%, V̇O2 peak 48.6±11.5 mL·kg-1·min-1) volunteered to participate in this study [...]
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In order to produce a large difference in CHO availability, pre-SE endogenous CHO stores were altered by a combination of exercise and diet" (Ferreira. 2016)
UPDATE: Exact macronutrient and energy content of the diets: Yes, it is a bummer that the exact macronutrient composition is not mentioned in the article, but I've gotten a pretty fast response from the authors who tell me that the low-CHO diet with 10% carbohydrate, 35% lipids, and 55% protein is not a high fat, but a high protein diet, while the high-CHO diet is, more or less, a low fat, low protein diet. Any conclusions about a truly ketogenic (as being in full ketosis 24/7 due to high fat, low carbohydrate and relatively low protein intakes) diet are thus unwarranted - too much protein (and likely gluconeogenesis) going on with only 35% of lipids and 55% of the energy from protein; wha is not surpring, though, is that a diet with the lion's share of energy being delivered in form of protein is rather ergolytic than ergogenic.In the test day, participants arrived at 8:00 am in the laboratory after a 12-h overnight fast and rested on a chair during 20 min for the assessment of resting V̇O2 value (Quark b2, Cosmed, Italy). Then, they underwent a 5-min warm-up at 50 W, followed by an SE at 115% of V̇O2 peak until exhaustion, which was assumed when participants were unable to maintain the pedal cadence above 60 rpm. Immediately after the test, they sat comfortably on a chair for 60 min. The V̇O2 peak was measured continuously from the baseline to the end of the 60-min post-exercise period (Quark b2, Cosmed).
You have already seen the results of the O2 analysis (baseline values were similar for both groups) in Figure 1. So, I will stick to the results I haven't reported, yet:
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- total mechanical work was greater in the high-CHO group (76.9±16.5 vs 50.9±9.4 kJ, P=0.001, ES=2.0 large, power effect=0.91) and
- the V̇O2 measured at exhaustion was slightly higher in high- compared to low-CHO diet (48.6±11.0 and 45.2±11.0 mL·kg-1·min-1, respectively, P=0.004, ES=0.3 small, power effect=0.08)
- Ferreira, G. A., et al. "High-CHO diet increases post-exercise oxygen consumption after a supramaximal exercise bout." Brazilian Journal of Medical and Biological Research 49.11 (2016).