Wednesday, October 30, 2013

Does Drinking Milk Pre-Meals Reduce Appetite?

Certainly that's what this study, Effects of milk as a recovery drink following exercise on subsequent appetite and energy intake in female recreational exercisers seems to conclude,
"In conclusion, the consumption of skimmed milk following 30 minutes of moderate-vigorous cycling exercise resulted in a reduction in subsequent energy intake, in female recreational exercisers."
But the thing is, it probably doesn't, at least not in the broad based way the conclusion is written.

It probably doesn't because what the study explored were the total calories consumed by female recreational exercisers who, an hour prior to an all-you-can-eat meal, drank either 600mL of skim milk or 600mL of orange juice.

Turns out, subjects who had a ginormous pre-load of milk instead of a ginormous pre-load of orange juice consumed 193 fewer calories (where the total included both the beverage's and the meal's calories).

So definitely, if you're planning to down more than half a litre of either juice or milk before your meal, it would seem that you'd be far better off with the milk.

But what about if your preload was water because, after all, 600mL of water has zero calories while 600mL of skim milk has 228 calories? My bet is that you'd consume fewer total calories because studies looking at the impact of caloric beverages vs. water and other zero calorie beverages demonstrate that indeed, we don't fully compensate for liquid calories (meaning drink calories with your meal and you'll consume more in the way of total meal time calories). In this study's case, if the choice had been water rather than milk, those sitting down to their all they can eat pasta meal would have needed to consume more than a cup more pasta to gather up milk's 228 calories.

What also seems impossible to me is that the study's authors weren't aware of the phenomenon of incomplete compensation for liquid calories when consuming a subsequent meal which in turn led me to wonder why their methodology didn't include a water arm, or a zero beverage arm for comparison. Could their omission have been purposeful, where the purpose would be to allow the authors to conclude that milk consumed post exercise is a wise plan for calorie reduction, this despite the very strong likelihood that doing so will almost certainly increase total calorie consumption for the combined meal and beverage?

So I asked one of the authors, Dr. Stevenson (far right in photo up above), on Twitter (@emmajstevenson), why there was no water arm,
But unfortunately, despite responding to other queries, she did not choose to respond to that one.