I'm 77, my wife is 73, she still triathlons, we've been taking Omega 3 for years. We're activists on our health. No meds. Weight spot on. We're retired, what is it we're supposed to be doing but take care of ourselves? Our son, 44, has contracted MS and is following prof. Dr. George Jelinek's "Overcoming MS". Emphasis on Omega 3 supplements is high to the extent of a vegan diet plus Omega 3 supplements plus a can of sardines (high on Omega 3) daily. There's an ongoing study program in Australia showing average 20% improvements in MS over 5 years with this program. Do note this is a low carbon low cultivated land lifestyle - wild caught sardines and salmon are not in short supply don't take fertilizer or arable land or pesticides or much energy to harvest. We do one 4 oz drained no salt added can three times a week. B12, by the way. Dr. Furhman's study is asking for vegan people that don't do Omega 3....good luck on finding them.

Oh, we exercise 6 days a week, my wife triathlons and does 5k races she's 73. I bike hills, I'm 77 plus fitness exercise. We certainly need healthy nutrition before biking so we don't "bonk" on the hills, and nutrition after exercising with weights & cardio to replace energy consumed. We feel fine. No meds. As in previous comment, we're vegans, no detox called for. No way "water" nutrition will work for us. And our BMI's are spot on (well, my wife is a bit light).

Atlhough McDougall mentions very strong arguments, I'm still not convinced whether to believe him

Detoxification takes place throughout the body. The liver is just one component in the system of toxin elimination. Also, detoxification is always taking place, not just when fasting.

Not taking in nutrients does not mean that the body has no nutrients at its disposal. The body has stores of nutrients in different places. Protein is stored in muscles, fat in fat depots, carbohydrates as glycogen in the liver and in muscles. Fat-soluble vitamins are stored with fat, and other vitamins and minerals are stored in the bones and in other cells. With adequate dietary nutrition the body stores all of the nutrients it needs continue functioning optimally through a fast. So the liver, blood, and other tissues and cells that are continually detoxifying call upon bodily stores of nutrients (and metabolism shifts to ketosis).

When water fasting, the body continues detoxification, just as it was doing before the fast. The difference is that the toxic load is reduced. All foods (and air, water) contain toxins that the body must eliminate, else humans would not breath, urinate or defecate. The difference is that the incoming toxic load is reduced since no food is being taken in. A portion of the energy of those bodily processes that are involved in detoxification, which previously was directed at food, is redirected to tissues of the body.

Your body was and is detoxing, both before and after your switch to a vegan diet.