Vegetarianism reduces risk for disease

The argument

The health case for vegetarianism rests on a substitution rather than on subtraction alone: what is removed from the diet matters, but so does what takes its place. Red meat has been shown to have high amounts of fat and cholesterol, and these are held to increase the risk of cardiovascular disease, obesity, cancer, Type II diabetes and other health issues. A diet high in fruits and vegetables supplies instead essential vitamins, minerals and fibers. The significance of this is that the two effects act on the same conditions in opposite directions: the foods that displace red meat are associated with reducing the risk of precisely the diseases red meat is said to raise. A vegetarian diet therefore does not simply avoid a harm, it puts a benefit in the harm's place, so the gain is doubled at every meal where the exchange is made. The outcomes claimed follow this pattern. Vegetarian eating has been shown to reduce the risk of death from ischemic heart disease, ischemic meaning that a tissue is not getting enough blood or oxygen, and to contribute to lower cholesterol levels, lower blood pressure, and lower rates of hypertension and Type II diabetes. These are not a miscellaneous list of advantages but a connected one, since cholesterol and blood pressure are among the mechanisms through which cardiovascular disease develops. Improving them is part of what reducing deaths from heart disease consists in, so the intermediate findings and the mortality finding support one another. Vegetarians are also reported to tend towards a lower body mass index than meat-eaters, which bears in turn on obesity. Taken together, proponents argue, the evidence points the same way across several distinct conditions at once, and reduced disease risk is accordingly among the clearest pros of vegetarianism.

Premises

Counter-arguments

Vegetarianism can be just as unhealthy as a normal diet. There are plenty of unhealthy foods, such as chocolate, potatoes, and other foods that are vegetarian. Meat actually contains lots of protein and nutrients that are difficult to get from plants. Being vegetarian does not necessarily make one healthy, and a healthy diet has nothing to do with eating meat or not.

Rejecting the premises

[Rejecting P1] The premise runs together processed and unprocessed red meat, which the evidence treats quite differently: the associations with colorectal cancer and cardiovascular disease are considerably stronger and better established for processed meat. Dietary cholesterol is also no longer regarded as the principal driver of blood cholesterol, and these causal claims rest on observational studies with the confounding that implies. [Rejecting P2] What supplies the benefit here is the fruit and vegetables, not the absence of meat, and the two are separable — a diet can contain both. The premise therefore supports a case for eating more plants rather than a case for vegetarianism as such. [Rejecting P3] The cohort findings are real but weaker than the phrasing suggests, and they carry a healthy-user problem the argument does not acknowledge: vegetarians in these cohorts also smoke less, drink less and exercise more. The large studies that adjust for this report reduced ischaemic heart disease alongside a higher rate of haemorrhagic stroke, and lower B12 and iron status. The counter puts the simpler version: the category admits diets of almost any nutritional quality.