Why Low Carb?
Study design & results in a nutshell:
5 weeks, low(ish) vs. high carb (40 vs. 58%) with the calorie difference split between protein (23 vs. 16%) and fat (37 vs. 27%). In other words, the low(ish) carb diet was higher in protein and fat. And there was 2 versions of each diet — a high and low glycemic index. Lots of crossing over; all in all, weak intervention but decent study design & execution.
Aaaand nothing drastic happened. Goal was insulin sensitivity, not weight loss.
1) The participants were relatively healthy at baseline. Anyone on meds was excluded. Average BMI 32. Mostly educated non-smokers. This population is expected to respond reasonably well to any diet (wrt body weight… see next point).
2) “Calorie intake was adjusted to maintain initial body weight.”
^^^this really knocks the wind out of low carb. One of the big benefits of cutting carbs is spontaneous appetite suppression –- two points here: 1) this effect is most prominent in obese IR; and 2) it is more relevant to weight loss. By not targeting insulin resistant and/or type 2 diabetics, and feeding specifically to prevent weight loss, I ask you this: Why Low Carb?
3) the biggest difference between the two diets was carbs (45% higher in low[ish] fat group), but the biggest difference from baseline, was protein in the LC group (53% increase). In other words, the Low Carb group had their carbs decreased from 50 to 40% of calories. *meh*
4) Body composition wasn’t assessed; so even if LCHP induced nutrient partitioning and improved body comp, we wouldn’t know it.
5) Everyone was eating cereal or oatmeal for breakfast, bread with most meals, and pasta or rice for dinner. What did you expect? Really?