Looking at things like this in isolation, i.e. just feeding someone more meat, doesn’t tell us very much at all – although some larger studies were cited, albeit with conflicting results.
The programme ended showing that, after eating a high-meat diet, the guy’s blood pressure was raised and his proportion of body fat was significantly raised. Looking at the body fat first; eating more meat will lead to a person being less well hydrated, since the meat will often take the place of some carbs and veg/salad, which hold water in the body. Fat percentage shows higher when a person is less well hydrated and could very well account for the 2-3% raise in his body fat. I imagine his fat percentage HAD gone up, as fat is very high in calories, but not as much as they said. Secondly blood pressure; blood pressure would be raised by clogging of the arteries, like lining a hosepipe with plaque so the hose is narrower and the water flow is more pressurised. I just can’t believe that his arteries would clog in that short a time frame. Neither blood pressure nor fat readings should be looked at as almost ‘one-offs’ they need measuring over time as both are subject to variables.
For me a large element of any risk from over-eating meat arises from just taking in more energy than the body needs, making it easier to store fat, internally or subcutaneously, including around the heart (let’s not get into the sugar debate here). Fatty meat makes it very easy to take in energy; meat such as sausages even moreso. A diet high in meat can often mean a diet that is not high in vegetables – certainly mainstream diets do not major on veg these days, and vegetables have myriad health benefits. The ‘a meal is not a meal without my meat’ brigade are very often not those who take a lot of exercise; so again there are other negative risk factors.
I can certainly see that processed meats could contribute to disease, such as cancer, from the effects of chemical reactions in the gut. Something they didn’t mention was the effect of a high meat diet on speed of transit through the gut. One theory is that because meat slows transit of food through the gut then potential carcinogens in food waste/faeces sit against the gut wall for longer and could contribute to cancer in that area.
Another point of concern was their comparison of meat and non-meat sources of protein. Comparing the amount of protein was a slightly pointless exercise, because it is EXTREMELY rare for westerners to have protein deficiency, veggie or not. Protein is abundant in food, and with the amount of food eaten we are far more likely to be having too much protein. The B12 argument – that meat is high in B12 – didn’t look at dairy sources of B12, though there was mention of cheese.
Anyway, it was an interesting watch. I just worry that people take these things at face value; though I really don’t mind if people eat less meat, so it could be worse!