How low-carbohydrate diets result in more weight loss than high-carbohydrate diets for people with Insulin Resistance or Type 2 Diabetes.

See The Battle of the Diets: Is Anyone Winning (At Losing?) for trials where insulin resistant people get more weight loss on low-carbohydrate diets than on high-carbohydrate diets, and insulin sensitive people get more weight loss on high-carbohydrate diets than on low-carbohydrate diets.

Although insulin is involved, it has nothing to do with "Hormonal clogs" or "Insulin fairies"!

The Aragon Insulin Fairy

The Energy Balance Equation

Change in Bodily Stores = Energy in - Energy out, where... 

Energy in = Energy entering mouth - Energy exiting anus, and... 

Energy out = BMR/RMR + TEF + TEA + SPA/NEAT

See The Energy Balance Equation to find out what the above terms mean.

People with Insulin Resistance (IR), Impaired Glucose Tolerance (IGT) & Type 2 Diabetes (T2DM) have no 1st phase insulin response to a sudden rise in blood glucose level. This introduces a time-lag into the negative feed-back (NFB) loop that regulates blood glucose level. If the input level rise-time is less than the time-lag in a NFB loop, the output of the NFB loop overshoots. This is standard NFB loop behaviour. Trust me, I'm a retired Electronic Engineer. I've observed this (too) many times!

1) On a high-carbohydrate or high-GL diet, blood glucose level rises rapidly, with a rise-time that's less than the time-lag in the blood glucose regulation NFB loop. Insulin secretion from the pancreas overshoots in a positive direction. The resulting postprandial hyperinsulinaemia results in rebound low blood glucose level. Rebound low blood glucose level results in postprandial hunger, as per Return of hunger following a relatively high carbohydrate breakfast is associated with earlier recorded glucose peak and nadir. Postprandial hunger results in over-eating. Energy in increases. Postprandial hyperinsulinaemia results in postprandial drowsiness. Energy out decreases. ∴ Bodily stores increase.

2) On a low-carbohydrate or low-GL diet, there are smaller fluctuations in blood glucose level. There is less postprandial hunger. There is less over-eating. Energy in decreases. There is less postprandial hyperinsulinaemia. There is less postprandial drowsiness. Energy out increases. ∴ Bodily stores decrease.

In addition, there is a loss of water weight due to a loss of liver & muscle glycogen. This can be up to ~3lb (it varies from person to person). The kidneys can also increase their output for hormonal reasons. This can increase water weight loss to ~5lb.


P.S. In Metabolic Ward studies, food intake is tightly controlled, so postprandial hunger doesn't result in over-eating. Energy expenditure is also controlled, so postprandial drowsiness doesn't significantly affect energy expenditure. This is why varying Fat:Carb ratios (with Protein held constant) makes no significant difference to weight in a Metabolic Ward. See Energy intake required to maintain body weight is not affected by wide variation in diet composition.


P.P.S. Inter-personal variations in postprandial hyperinsulinaemia, postprandial drowsiness & energy out explain the inter-personal variations in weight gain seen under hypercaloric conditions.