In our household, Friday night is steak night. A grilled medium-rare fillet steak, served alongside salad and homemade chips marks the start of weekend.

It’s none of that cheap supermarket stuff, mind you, but locally sourced meat from ‘happy cows’.

This is a special treat that we save our pennies for, but, like so many indulgences in life, it’s difficult not to feel a little guilty. Once seen as a healthy choice, red meat eating is now the medical villain. Some even say it’s as bad for you as smoking.

We’ve long known the virtues of eating right. Since 1958, researchers have closely followed a cohort of 12,000 people from different countries and cultures. Called the ‘Seven Countries Study’, it is still going today and the results so far have told us more about healthy living than practically any other investigation. For example, we now know that a ‘Mediterranean diet’, consisting of plenty of vegetables, fruits, beans, whole grains, olive oil and fish, goes hand-in-hand with a healthier life.

Conversely, we Northern Europeans and Americans have blighted ourselves with heart disease, stroke and cancer because of our love of red and processed meat.

Which, when you think about it, is a little odd. Nutritionally, red meat is packed with good things. Calorie-for-calorie, there are few sources of protein to beat it: one serving of lean beef has only 150 calories yet is loaded with essential nutrients vitamin B12, zinc, iron, phosphorous and selenium. But, it is the stuff that makes red meat tasty that also makes it harmful: the fat.

Saturated fat is bad for the arteries. It’s easy to spot a ‘saturated’ fat because it is usually solid at room temperature (butter, cheese, and the white fat on meat, for example). Liquid vegetable and olive oils are ‘unsaturated’ and better for you. The healthy solution is to trim the fat off, but that’s not the whole story.

The twist in this tail (pun intentional) is how many researchers fail to draw a distinction between different red meats – something newspaper reporters also usually fail to mention. Long term studies, including the Seven Countries Study, generally lump red meat and processed meat together in the results.

Now, you don’t have to be Gordon Ramsey to know that a meatball and a steak are very different things. For one thing, burgers, sausages and processed hams are usually made from a sludge of minced up, high fat meat that has been squeezed through a tube. (In 2012, DNA tests revealed that a packet of Tesco meatballs contains the meat from over 150 cows!). And that’s before salt, flavourings and preservatives are added.

And while there is presently insufficient evidence to separate the long term health effects of processed vs non-processed meat, most experts recommend a proper cut of meat over a sausage.

It also is recommended to eat no more than 500g of red meat (including beef, lamb and pork) each week. This works out at 70g a day – the equivalent of three slices of ham, one lamb chop or two slices of roast beef.

Personally, I’m certain that the occasional slice of lean red meat does you good. Should science ultimately prove me wrong then I’ll happily eat my (leather cowboy) hat. Which would make for a very interesting Friday night.