If you’re a carnivore who salivates at the aroma of meat sizzling in a pan, then a high protein diet - promising weight loss and the chance to eat more of your favourite foods - might sound like a dream come true.
But do these popular, protein-pushing diets actually promote good health?
“Diets which advocate proteins at every meal and usually, a form of meat protein, are a concern,” says Bowel Cancer Australia nutritionist Teresa Mitchell-Paterson.
Too much meat protein could heighten your risk of bowel cancer (also known as colorectal cancer) and have other ramifications for your health with the loss of fibre and calcium in your skewed nutrition intake.
“Diets which advocate having proteins at every meal and usually, a form of meat protein, are a concern."
A 60kg person should eat 48g of protein per day, which can rise to 1.2g per kilo per day - 72g of protein - for those exercising heavily. Someone weighing 80g and exercising a lot, on the other hand, can follow those 100g per day of protein diets - with provisos.
But what does that amount of protein actually look like?
“Let’s say you eat one egg, which roughly contains about 10 grams of protein and a 100-gram piece of meat, which contains about 20 grams of protein," says Mitchell-Paterson.
"Just with those two foods, you’re already at 30 grams of protein a day. If you weigh 60 kilograms and you are having nuts and seeds throughout the day, a yogurt and cheese, that’s possibly another 20 grams of protein [and a total of 50 grams of protein]."
Mitchell-Paterson stresses that dieters should calculate their personal allowances to ensure that a high protein diet doesn’t tip them over the recommended limit.
Not all proteins are equal
When it comes to assessing the safety of high protein diets, it’s essential to consider the type of protein eaten, not just the quantity.
Mitchell-Paterson says plant-based proteins - such as legumes or grains - are OK to consume at will, as it is thought that they may lower your risk of bowel cancer.
However, she explains that most high-protein diets usually focus on meat, not plants, and are low in carbohydrates.
“If you want to get your protein from plant sources, you’ll have to consume a lot of legumes and grains! If you consumed 75 to 100 grams of chickpeas, you’d still only consume six to seven grams of protein. So it’s a little harder to get the quality and quantity of protein from plants, although many vegetarians do it very well.”
She adds that if protein shakes are plant-based, dieters also have the green light to go ahead and consume.
“Just be aware that you can drink around 30 grams of protein in one drink.”
But dieters should be aware of potential drawbacks when sourcing protein from red and processed or cured meats.
She says, "High meat protein diets above the recommended range have been linked to higher cholesterol levels, heart disease, kidney problems and osteoporosis."
According to the WCRF, you increase your risk of bowel cancer by 17 per cent for every 100 grams of red meat you consume per day; and 18 per cent for every 50 grams of processed meat consumed per day.
“To lower your risk of bowel cancer, I’d encourage everyone to stick to the recommendation of having 500 grams of red meat and processed meat [combined] a week,” she says.
Red meat includes beef, lamb, pork, veal, mutton, horse and goat. WHO also recommends against the consumption of charred (common during barbecuing) or burnt red meats and chicken.
“You can imagine that, in a typical Australian diet, we are eating a lot of red meat, over and above the recommendations to reduce your risk of bowel cancer," says Mitchell-Paterson.
"People might have a steak at lunch and a pork stir-fry for dinner. Now that’s a total of around 400 grams of red meat, consumed in just one day.
"Or, if you buy a ham sandwich each day, you just need to look at the amount of meat you get. There’s definitely value for money but it’s piled high with ham. So eating a ham sandwich is a risk factor for bowel cancer if you’re doing that every day.
“So to lower your risk of bowel cancer, I’d encourage everyone to stick to the recommendation of having no more than 500 grams of red meat and processed meat, combined, a week."
Bowel Cancer Australia CEO Julien Wiggins emphasises that high protein diets must adhere to the recommendations and daily red and processed meat limits to be healthy.
“We are not saying you should give up red meat, as we all need a balanced diet,” says Wiggins. “But we do know that a high consumption of red meat and processed meats is a high risk factor for bowel cancer.”
Around 15,000 people are diagnosed with bowel cancer every year, and that figure is rising. One in 13 Australians will contract bowel cancer by age 85, with the incidence in 2016 estimated by the Australian Institute of Health and Welfare at 62 cases per 100,000 persons. Men are more likely to contract it than women.
Wiggins says up to 75 per cent of all bowel cancers are influenced by diet and lifestyle.
“The bowel is your body’s plumbing, so if you aren’t aware of what you are putting into your body, you could put yourself at risk of bowel cancer.”
June is Bowel Cancer Awareness Month. For more information, visit bowelcanceraustralia.org or call Bowel Cancer Australia on 1800 555 494.