Wednesday, June 26, 2013

Night-Time Carb, Whey or Casein Drink Boost Morning Energy Expenditure & Modulates Fatty Acid Oxidation

Carbs, whey and casein, is everything better than not eating before bed?
As a SuppVersity reader you know for quite some time that eating carbs past 6PM is not going to make you fat (go back and learn more). However, what you probably don't know is what exactly happens when you have 33g of vanilla flavored maltodextrin powder right (30 min) before bed? And how does that compare to 30g of whey protein or casein?

Interesting questions, right? Well, good for us that Takudzwa A. Madzima, Lynn B. Panton, Sarah K. Fretti, Amber W. Kinsey and Michael J. Ormsbee from the Department of Nutrition, Food and Exercise Sciences at the Institute of Sports Science and Medicine of the Florida State University alrady have some answers.

Whey, casein or carbs before bed?

The study was designed to investigate the extent to which a single serving of WP, CP, CHO or a PLA before sleep affects satiety and metabolism, independent of exercise, in eleven physically active (at least 4 d/week and 50min/d of self-reported moderate-to-vigorous physical activity for >12 months) college-aged men (age: 23.6 y; BMI: 25.8 kg/m2; body fat: 16.3%). The scientists hypothesized...
"that consumption of protein at night before sleep would have a positive impact on next-morning metabolism and appetite to a greater extent than that of CHO or a PLA beverage" (Madzima. 2013)
And if you take a look at the data in figure 1 you will have to concede that assumption was at least partially right.
Figure 1: Visual analogue scale of hunger, satiety and desire to eat (Madzima. 2013)
Yep, you are right: Based on the subjective hunger, satiety and desire to eat assessment, casein is by far the best choice, but even having some carbs pre-bed could offset potential early morning binges by reducing the desire to eat by -19% (vs. -19% for whey and -24% for casein compared to placebo).

Is this just a psycho thing or are there any physiological mechanisms involved, as well?

Now, it goes without saying that the thing you are probably more interested in are the changes in energy expenditure and the effects on substrate utilization (carbs vs. fat) I hinted at in the headline already. So, let's see what those looked like and whether they could actually explain the "satiating" effects.
Figure 2: Resting energy expenditure (REE) and respiratory exchange ratio (RQ: higher values = higher glucose oxidation, lower fat oxidation) on the morning after the dietary intervention (Madzima. 2013)
While the effects on the respiratory quotient and thus the rate of glucose to fatty acid oxidation is negligible, the +4-6% increase in resting energy expenditure is something to keep in mind. Not so much because this is going to make you lean (in isolation it certainly isn't), but rather in view of the fact that it is another scientific result that clearly contradicts the "popular belief that it is advantageous to limit energy intake in the evening" (Madzima. 2013). So the scientists are right to conclude that
"[...] it is convenient to hypothesise that the improvement in morning resting metabolism may further aid in the maintenance of and/or improvement in body composition and thereby provide a competitive advantage in healthy, physically active young men." (Madzima. 2013)
But they are also right when they state that both studies to investigate the impact of liquid energy intake v. solid energy intake and different combinations of macronutrients, as well as long-term studies of night time feeding would have to be conducted before anything definitive can be said about the real world results these overall minuscle changes will bring about.

Apropos real world + long-term results, you do remember that a 40g casein shake might help you build an additional 3.2kg of lean muscle mass in a year... if you oversimplistically extrapolate the acute protein synthetic respone Res et al. observed a 2012 study on the effects of a pre-bed casein shake (see "3.2kg of Lean Mass Over Night W/ 40g of Slow Digesting Protein 30min Before Bed!? Over One Year, a Positive Nitrogen Balance and +20% FSR Could Make It Happen!" (read more).