Saturday, 23 February 2013

can vegetarianism be unhealthy?

There was a very interesting article in the Independent newspaper on Thursday (21/02/13) titled From vegetarian to confirmed carnivore where John Nicholson stated that when he was eating a low-fat wholefood vegan diet he felt ill. He became obese and had irritable bowel syndrome (IBS), diarrhea, fatigue and headaches. His partner, who shared his way of eating, had depression and mood swings.

They decided to ditch the wheat, rice and potatoes and eat lots of meat, butter, cream, lard and goose fat. He felt better straight away and lost lots of weight. His cholesterol levels went down. This seems on the face of it to contradict everything that I have been saying on this blog, about people eating less meat and more starchy foods and vegetables. However, I think I can understand what is happening here.

John seems to have gone from one extreme to another. From veganism to eating lots of meat and animal fat. When people make radical changes in the way that they eat, often excluding whole food groups, they often gain weight or lose weight without trying. They may be getting more calories or fewer without knowing.

The placebo effect might explain some of why John started to feel a lot better straight away. I don't want to dismiss what he says though. It is possible that John had an iron or zinc deficiency which was rectified as soon as he started eating meat, especially as his first meat was ox liver. It might even be that he wasn't getting enough protein, although it's not that difficult to get enought protein on a vegan diet. Another possibility is that he was suffering from an allergy to wheat.

If he had been eating soya products, that might have caused problems. Soya contains phytic acid which reduces our ability to absorb iron and zinc and trypsin inhibitors which reduce our ability to digest protein. This might not be a problem with traditional foods like miso, tofu or tempeh, but might be more of a problem with other ways of eating soya.

John seems to have moved to what is in effect the Atkins diet. In the Atkins diet people do not try to control calories but eat as much meat and animal fat as they like. The main thing they are trying to avoid is carbohydrate. It is a low-carbohydrate diet. When you digest carbohydrate, glucose enters the bloodstream. If you have too much glucose in your bloodstream your body needs to remove the excess or it will cause problems. Your pancreas secretes the hormone insulin which tells the body to remove some glucose.

In most people insulin and glucose levels rise and fall. Too much of this causes problems though. Obesity is only one problem that can happen when we have big rises and falls of insulin and glucose. Obesity can give rise to other problems. It is now recognised that this is one of the biggest causes of ill health.

People on the Atkins diet tend not to eat vast numbers of calories because the diet is less varied than a normal diet. They can easily get bored with it or even a bit nauseous contemplating the prospect of yet more meat and fat. It is often said that people crave fat, but a lot of the fat we eat is hidden. If you eat a slice of cake, you don't realise how much fat is in it because the flavour is masked by sugar or something acidic such as lemon. We eat so much fat not because we love it so much but because we don't know it is there.

I don't have a problem with the Atkins diet. It does seem to work at helping people to slim. I do wonder about the long-term effects of staying on the Atkins diet though. I'm not just worried about heart disease and strokes, reducing protein has been linked to increased longevity.

I wonder if it would work just as well if instead of meat they ate fish, and instead of eating butter and lard they ate avocados and olive oil. In Crete people traditionally got lots of their calories from olive oil and far from harming them it seems to have contributed to health and long life.

Also, there are some forms of carbohydrate that are better than others at not flooding your bloodstream with glucose. Starch is better than sugar, and the amylopectin form of starch is better than the amylose form. You can measure the effect that a food has on your blood glucose levels. A low glycemic index (GI) is better than a high glycemic index. Long-grain rice is better than short-grain rice. Brown rice is better than white rice. Pasta and porridge are good too. If you eat some low GI forms of starch it won't have too bad an effect on your blood glucose levels.

Vegetables can seem to have a high GI but really they are mostly OK. Baked potatoes are not good though. So I shall continue to eat my long-grain rice and pasta, together with my pulses and vegetables. I do eat meat, cheese, fish and eggs sometimes but not every day. What John Nicholson has said in no way invalidates what I have stated on this blog about the problems of trying to feed everyone on the planet with lots of meat. We can't feed 7, 8 or 9 billion people with a diet high in meat.

A good point that John makes is that not everbody is the same. People vary as to what sort of foods they thrive on. I think it is likely that some people digest starch more readily than others. If so, they are less likely to thrive on a high starch diet even if it is low GI.

In case people are thinking that they can just add butter and cream to their normal foods and get away with it, it doesn't work like that. If you want to eat lots of meat and fat and lose weight then you would have to go on an extremely low-carbohydrate diet, or you will just put on weight.

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