If you're feeling tired on a diet that is mostly comprised
of fats and proteins, this could be due to low stomach acid, which leads to
improper protein
digestion.
This can be caused by a number
of things, from having a deficient amount
of enzymes needed to break down specific carbohydrates,
fats or proteins which lead to
improper digestion and undigested food in the large intestines which results in gas production and bloating.