Everybody knows.........Part 2

.........that ketogenic diets like the Atkins diet destroy your kidneys and rot your bones, right? Wrong!
.........that the Atkins diet causes ketoacidosis which is a very dangerous condition requiring urgent hospital treatment, right? Wrong!

There's a lot of nonsense spoken about ketogenic diets by people who really should know better. I suspect that they have been taught wrongly at uni or med school as per the quote in Everybody knows.........Part 1.

Benign Dietary Ketosis is NOT Ketoacidosis.

Consider the following four cases:- Note: Figures are from "Introduction to Nutrition and Metabolism" By David A Bender (Senior Lecturer in Biochemistry, UCL)

1) Healthy human, fed state: Glycogen stores are replete. Serum glucose = ~5.5mmol/L. Serum fatty acids = ~0.3mmol/L. Serum ketones = 0mmol/L. No gluconeogenesis is taking place. Amino acid pool is replete. Cortisol level is normal so there is no loss of muscle mass.

2) Healthy human, fasting for 7 days: Glycogen stores are depleted. Serum glucose falls to ~3.5mmol/L. Serum fatty acids rise to ~1.2mmol/L. Serum ketones (mainly D-3-hydroxybutyrate) rise to ~4.5mmol/L (not high enough to cause acidosis). Gluconeogenesis is occurring. Amino acid pool is depleted. Cortisol level is high, causing slow loss of muscle mass. This is bad ketosis.

3) Healthy human, low-carbohydrate diet: Glycogen stores are depleted. Serum glucose falls to ~5mmol/L.
Serum fatty acids rise to ~1.2mmol/L. Serum ketones (mainly D-3-hydroxybutyrate) rise to ~4.5mmol/L (not high enough to cause acidosis). Gluconeogenesis is occurring. Amino acid pool is replete (due to protein intake). Cortisol level is normal so there is no loss of muscle mass. This is good ketosis.

4) Human with untreated type 1 diabetes: Glycogen stores are depleted. Due to lack of insulin, the Glu-T4 transporters in cells cannot move to the surface so glucose cannot enter cells. Serum glucose = >20mmol/L. This causes major damage to kidneys, arteries, eyes, nerves etc by cross-linking with proteins (glycation) resulting in major disability and eventual death. As the body is forced to run on fatty acids & ketones, metabolic processes are out of control and ketones rise to much higher levels than in 2) or 3) (I don't know how high exactly) resulting in acidosis and eventual death. This is ketoacidosis.

Conclusion: Low-carbohydrate, very-low-carbohydrate & ketogenic dieting is similar to fasting in that serum glucose levels are lower than normal and glycogen stores are depleted. The body is encouraged to burn less glucose and more fatty acids & ketones, but the metabolic processes are all under control. The big difference between low-carbohydrate dieting and fasting is in the amino acid pool and cortisol levels.