BBC Horizon’s reporter, Michael Mosley, decided to investigate this, both by speaking to the ‘experts’ and also by putting himself on a moderately high meat diet, twice the ‘recommended’ amount, from red and processed meats such as beef, lamb, pork, bacon, salami, sausages, ham.
Let’s put this into context. The average portion of meat is 80 grams, about the size of a pack of cards. The average Brit eats 70 grams of red or processed meat a day, and that’s excluding white meat. I recommend meat a maximum of three times a week (average of 34g a week) and ideally less, choosing mainly white meats, no processed meats.
A quarter of people in Britain eat 130g of meat a day – in other words an average of two meat servings per day. That’s the amount Michael Moseley put himself on for a month to see what it would do.
The ever popular low-carb diets such as Atkins, on average, recommend 80g two or three times a day, so that’s at least 160g, and often 240g or more.
At Loma Linda University, Dr Gary Frazer has been studying 7th Day Adventists, who live much longer than most people. Most, but not all, are vegetarian. Comparing 7th Day Adentists who did eat meat to those who didn’t, his research showed that eating beef three times a week is associated with double the risk of heart disease - a difference of 4-5 years life expectancy (that is an average of less than 60grams a day so not even that high).
He interviewed Professor Walter Willett, from Harvard Medical School. He summised that in large US based studies the risk of death and disease from eating processed meats are several times worse than other meats, and that eating 35g a day of processed meat (eg a serving every other day), is associated with a 20% increased risk of premature death – mainly from cancer.
During his childhood, growing up in the American west, he often ate meat three times a day. Now, he eats red meat a few times a year. You get the impression he avoids processed meats.
Mosley then talks about the very large European Prospective Investigation into Cancer (EPIC) study which followed half a million people, in 10 countries for more than 12 years, and found that moderate meat consumption did not correlate with lesser life expectancy and concluded eating a little meat might even be slightly better for you than none, said Mosley. (Actually the risk from red meat, above 80g a day, slightly increased risk of mortality, while 160g or more significantly increased risk. So, even for red meat, there is a warning about not having it so often.)
Both the American and European studies, however, agreed that moderate amounts of processed meat does increase heart disease and cancer.
But why would meat, especially processed meat, increase cancer? The Horizon programme investigated:
- PAHs (polyaromatic hydrocarbons) from the smoking sticks to meat, which can damage DNA. By the way, these also form from barbecued meat fat dripping onto coals, and ‘smoking’ the meat. These are similar carcinogens to smoking.
- Nitrosamines form from the combination of nitrites and amino acids
- And added salt used to cure the meat. Sodium nitrate is added as well.
There is a fourth factor, which was not mentioned, and that is the very high levels of acrylamide formed in burnt meat – the crispy stuff. This is also a known carcinogen.
Michael Mosley’s health check up results, after a period of 4 weeks showed:
- No significant increase in stool levels of n.nitroso compounds (what you measure to reflect nitrosamines in the gut), which are associated with colorectal cancer – the gastroenterologist was surprised but said his high fruit and veg intake, hence fibre, may have protected him.
- His cholesterol went up from 6.2 to 6.8 mmol/l (and mainly an increase in LDL) – that’s a 10% increase
- His body fat went up by 3kilos, mainly in the trunk area (7lbs). That’s almost 2lb weight gain a week.
- His blood pressure went up 118/69 – 141/81. That’s about a 18.5% overall increase.
His conclusion was to go back to eating little meat and no processed meat. I think this is good advice.
If you are concerned about the dangers of a low carb, high fat, protein diet read my extensive article in this month’s newsletter available to members of my 100% Health Club.