One of the interesting questions that has arisen is that of what “too much” meat consumption might be. It is often repeated, and I have done this myself, without thinking too deeply, that there are many people in the world who are malnourished and could do with more meat in their diet, and that there are also those who eat “too much” meat.
Diets are really complicated to study. Firstly, most surveys rely on people’s recall of what they ate over a given period, which is open to poor recall and misrepresentation
(i.e., some people will deliberately say their diet is what they think
is better.)
Secondly, we eat foods, not individual nutrients, and in general, we do not measure portions accurately. Different foods interact with each other in different ways, and the number of combinations and thus interactions in a diet is enormous.
One thing we can study a little more accurately is the impact of a dietary recommendation, at least in terms of its nutritional adequacy. We know the level of nutrients, macro and micro that are required for different ages and gender groups.
Dietary guidelines were initially formulated to recommend levels of different food groups to arrive at an overall healthy intake that meets the population’s needs and results in lower levels of non-communicable diseases.
The dietary guidelines for Americans were first issued in 1980 and have been updated every five years since, and most other high income countries followed soon after. The content varies as research throws more light on health impacts of different foods, not always consistently. In general, they have favoured a reduction in saturated fats, and more recently a reduction in processed and red meat, following publication of IARC’s findings that processed meat is carcinogenic (on a long list of carcinogens).
The fact that processed meat probably only causes 5% of the number of cancers per year as alcohol, or 12.5% as many as air pollution is rarely dwelt upon. Red meat is considered “probably carcinogenic” (level 2A) which is on a par with drinking hot beverages above 65°C (149°F), or one level above aspartame.
Of course, there are other health concerns that one reads around meat consumption, mostly to do with the saturated fat content, but I have been surprised to read people even associate red meat consumption with type 2 diabetes. It appears to be conflating two entirely different things, namely excessive consumption overall with a high intake of red meat. The link between obesity and type 2 diabetes is well established, and it is no surprise to find that a proportion of obese people are found to have high intakes of red meat.
It has been said of dietary guidelines that the one thing which everyone agrees on is that no one follows them. That is not entirely true. There has been a significant shift away from saturated fats and a reduction in red meat consumption in many HICs, although this does not coincide with noticeably better health outcomes. Government institutions tend to be required to provide diets that are in line with guidelines.
In recent years, there has been a trend to include environmental impact as a parameter in dietary guidelines. This is a significant challenge for those involved in their formulation, first because they primarily involved nutritionists to begin with, and secondly because it is rather hard to generalise about the environmental impact of a whole class of products.
In following this path, there have been further challenges, and ensuring nutritional adequacy while sticking to putative environmental boundaries is one of them. The most high-profile diet that aimed to achieve “planetary health” i.e., both environmental and human health in recent years, was the EAT Lancet diet, which has been found to be deficient in a variety of macro and micro nutrients.
A paper by two of the members of our nutrition panel, Ty Beal and Marion Herrero , and other colleagues, have shed light on the role of animal-source foods in diets using this environmental approach. Further, a recent review article looked at 56 papers covering micronutrient intake and concluded that “Lower intakes and status of micro nutrients of public health concern are a potential outcome of dietary changes to reduce environmental impacts. Adequate consideration of context and nutritional requirements is required to develop evidence-based recommendations”.
We are keen to advocate for overall healthy diets that include red meat without negative environmental consequences, and doing so requires an understanding of healthy ranges of intakes and the trade-offs between them. This is an active field of research, so it will probably end up being a position that requires refinement over time.
