Carbohydrates on the other hand are our main source of energy, but there is a huge health-distinction between a high carb' diet from natural sources such as fruits (complex carbs') which are health enhancing/promoting, and refined/processed carbohydrates from (for example) white-bread, white-rice, pasta and cakes, which are disease-causing................. http://www.diseaseproof.com/archives/debunking-diet-myths-lowcarb-diets-make-...
Processed carbohydrates, lacking in fiber, also fail to slow Sugar absorption, causing wide swings in glucose levels.
Insufficient carbohydrates in the diet will also not allow the body to "run" properly, so it produces ketones: an emergency fuel that can be utilized in times of crisis, as in Water or dry fasting.
Fresh fruits, beans and legumes, whole grains, and root vegetables are all examples of foods whose calories come mainly from unrefined and complex carbohydrates. It is the nutrient-per-calorie ratio of these foods that determines their food value.
There is nothing wrong with carbohydrates; it is the empty-calorie, or refined-carbohydrates that are responsible for the bad reputation of carbohydrates generally.
Your comment that..........
"High carbs raise triglycerides and lower HDL cholesterol, leading to heart disease"..........
.........is true, but ONLY by eating refined/processed carbohydrates and NOT complex carbs' from natural plant-based food sources.
A recent study published in the Proceedings of the National Academy of Sciences found that restricting calories (a plant-based diet of fruits and vegetables and therefore high in carbs') by 30 percent, decreased levels of triglycerides and increased HDL.
(Verdery, R. B., D. K. Ingram, G. S. Roth, and M. A. Lane. 1997. Caloric-restriction increases HDL2 levels in rhesus monkeys. Am. J. Physiol. 273 (4 pt. 1): E714–19; Ramsey, J. J., E. B. Roecker, R. Weindruch, and J. W.)
The B12 issue and vegans......
Vegans: meaning anyone who consumes no animal products, doesn't always make for a healthy diet; but if this diet is exclusively plant-based, then B12 deficiencies do not arise, and especially so if the diet is combined correctly.
B12 is sourced in miniscule amounts from plants and is secured primarily from that produced within the body. The stomach secretes a substance called "intrinsic factor", which transports the B12 created by the bacterial flora in our intestines.
Putrefaction/fermentation from improperly combined foods hampers this secretion of "intrinsic factor" in the stomach, and retards the production of B12 resulting in this deficiency.
Our actual need for Vitamin B12 though is so minute that it is measured in micrograms (millionth of a gram)or nanograms (billionth of a gram). One milligram of B12 will last over two years, and healthy individuals usually carry around a five-year supply.