Vegan is very healthy: Things to think about

Vegan diets are among the healthiest in the world. Plants are high in nutrients (specifically "phyto" i.e. "plant" nutrients), digest slowly so that blood sugar levels do not fluctuate rapidly and (due to their fiber content) are very filling, resulting in a natural inhibition of hunger and reduction in caloric intake without ever having to count calories or diet. Five of the six unsaturated fat sources (see my blog article in the "dietary fats" thread) are vegan sources. Soy protein quality is very high, and half the calories in soy is protein (protein quality in quinoa is high as well but only 1/6 of the calories are protein). Even an athlete competing at the National level can find their full nutritional support in a vegan diet so long as the macronutrients are kept in balance with each other (true of any healthy diet) and enough calories are consumed to keep up with the training. Studies indicating improved exercise recovery with animal-derived protein are consistent with nitrogen balance studies with non-athletes showing that you need a bit more soy protein than you would animal protein to regenerate tissues, which simply reflects the slightly lower bioavailability of soy. All living cells, including plant cells, contain protein, and combining grain with legume sources (bread and nut butter, lentil and naan, beans and rice) improves the resultant amino acid profile of the meal, which is why grains and legumes are called "complimentary proteins." While no studies have shown exactly how much complementary protein together with soy protein it would take to optimize high levels of athletic training, my personal recommendation is to simply use the upper limit of recommended protein intake provided to us by the American Heart Association, ranging from an upper limit of 20% of total calories to as high as 30% [1956-2000 Meta-Analysis, Circulation, 104 (2001) 1869]. Vitamin B-12 (cobalamine) is produced by micro-organisms in animals so vegan diets are low in B-12 so this vitamin should be consumed by supplement (to achieve the standard 'Recommended Dietary Allowances' or the new 'Dietary Reference Intakes' that have replaced the RDAs).