Again, the claim is if you eat 500 or 600 calories a
day two
days a week, and do not overcompensate
during the
rest of the week then you'll steadily lose
weight.
Adhering to these traditional concepts the US Department
of Agriculture has concluded that diets, which reduce calories, will result in effective
weight loss independent
of the macronutrient composition, which is considered less important, even irrelevant.14 In contrast with these views, the majority
of ad - libitum studies demonstrate that subjects who follow a low - carbohydrate diet lose more
weight during the first 3 — 6 months compared with those who follow balanced diets.15, 16, 17 One hypothesis is that the use
of energy from proteins in VLCKD is an «expensive» process for the body and so can lead to a «waste
of calories», and therefore increased
weight loss compared with other «less - expensive» diets.13, 18, 19 The average human body requires 60 — 65 g
of glucose per
day, and
during the first phase
of a diet very low in carbohydrates this is partially (16 %) obtained from glycerol, with the major part derived via gluconeogenesis from proteins
of either dietary or tissue origin.12 The energy cost
of gluconeogenesis has been confirmed in several studies7 and it has been calculated at ∼ 400 — 600 Kcal /
day (due to both endogenous and food source proteins.18 Despite this, there is no direct experimental evidence to support this intriguing hypothesis; on the contrary, a recent study reported that there were no changes in
resting energy expenditure after a VLCKD.20 A simpler, perhaps more likely, explanation for improved
weight loss is a possible appetite - suppressant action
of ketosis.