These days, it’s hard not to stumble on high protein diets. There are so many to choose from, and they’re often touted as the be-all-and-end-all solution to better health and long-term weight management. But what’s the science behind these diets, and are they safe – and doable – long-term?
Georgie Moore, 12WBT’s accredited practising dietitian, says no. High protein diets may sound great, but they’re simply another way of reducing your calorie intake by cutting out all sorts of other foods. “A high protein diet is just one more ‘solution’ to a weight problem. Any diet that causes you to eat less energy than you use will lead to weight loss,” she explains.
While protein is good for you, Georgie is dubious about the nutrition-rich foods you have to give up to go high protein – often whole food groups such as carbohydrates and dairy fall by the wayside – and the claims that often come packaged with high protein, low carb diets.
“For instance, the creator of one well-known high protein diet claims you’ll be free of almost all health issues, including autoimmune diseases and even skin cancer!” says Georgie. “He also declares that cholesterol is not necessarily linked to heart disease, but this is incorrect.”
Busting the High Protein Diet Myths
High protein diets have been touted as the best fat burners because protein is harder to digest so it burns more calories and keeps you full for longer. This is true. And most people starting a high protein diet do lose weight because they are less hungry, but also because eating few or no carbs forces the body to use some of its glycogen stores instead, and also releases water.
This can be harmful. In cutting out carbs, Georgie says you’re cutting out the brain’s favourite fuel. Plus, consuming more protein than you need can lead to increased levels of uric acid in the blood, raising your risk of gout. Too much protein can also lead to higher cholesterol levels.
That’s not to say that we should all eat exactly the same amounts of the various macronutrients (such as protein or carbohydrates). The latest Australian Dietary Guidelines were revised this year and there’s more leeway for us to work out what we need based on our gender, age and activity level, says Georgie.
“The guidelines reflect that we move a hell of a lot less than we used to, and so the recommendation for carbohydrates has decreased. Generally speaking, to keep your body functioning you cannot live without carbs, but those who are less active will need less fuel and thus fewer carbs,” she explains.
The Role of Protein in our Diet
Protein is an important part of your diet: it’s the building block of bones and teeth. It takes care of muscle repair, and regulates certain chemical reactions in the body. Protein is also a key player in helping the immune system fight off bugs.
“Protein is essential for the body to build, grow, repair and maintain every bit of us, including hair, skin, blood – everything – so it’s vital that we eat enough each day,” says Georgie. “The problem is, most Aussies eat way more protein than they actually need.”
High protein diet fans or bodybuilders operate under the belief that if a little protein’s good for you, a lot must be better, and on a diet like Atkins or the Dukan Diet, protein allowances may be unlimited.
But Georgie says we need to be careful of how much protein we’re consuming and how often. “We do need a certain amount, and we should ‘drip-feed’ it throughout the day. It’s like alcohol: your body can only process certain amounts of protein in one go – about 25g to 30g of protein in one sitting, which equates to about 100g of red meat or chicken,” she explains.
Eating more protein than your body can process is pointless, as it can’t be stored like carbs. “So, for those who are consuming a high protein diet, tucking into a 500g steak is not going to be of any more benefit to you than a 100g steak;” Georgie explains, “because your body just expels the extra protein it can’t process right then.”
How Much Protein do we Need in our Diet?
Depending on how active we are, generally speaking we need 0.8g to 1.2g of protein per kg of body weight per day. For a 70kg woman or man, that would be around 70g of protein per day, give or take a couple of grams. What does 70g of protein actually look like? Let’s see.
How Much Protein is in My Food (g)
1 large egg = 6g
100g chicken = 28g
50g cooked lentils = 8g
100g grilled salmon = 22g
25g cheese = 7g
TOTAL = 71G
Using the list above, you could easily space out your protein requirements through the day – you could enjoy an egg for breakfast on some grainy toast, grilled chicken and a lentil salad for lunch and salmon for dinner with veggies, plus a little cheese for a snack.
“For those who eat red meat, as long as you’re getting around 500g of red meat a week, two to three serves of fish per week and two to serves of low fat dairy per day, there is no need to be adding additional protein-rich foods to your diet,” says Georgie.
Vegetarians need to be especially aware, though, of making sure they have enough protein with their meals, because plant-based protein is not as easily absorbed. Vegetarians should bulk out their meals with protein-rich foods such as dairy, eggs, tofu, nuts, seeds and legumes. Smaller amounts of protein can also be found in breads, grains and vegetables.
A Diet With Too Little … or Too Much
You’ll soon notice the signs if you’re not getting enough protein in your diet, says Georgie. “Eating too little protein will lead to feelings of fatigue, poor wound healing and poor skin and hair – just poor health in general,” she says.
And if you eat too much, or are on a high protein diet that drastically reduces your carb intake, you can put your body into a process known as gluconeogenesis… which is when the body is forced to turn amino acids into glucose. “This is when the body is forced to turn protein into carbs to feed the brain,” says Georgie.
“This leads to a state known as ketosis. If the body is in ketosis for a prolonged period, it can lead to health problems such as heart disease as well as lack of concentration, moodiness and low blood sugar levels. The kidneys filter excess protein, turn it into nitrogen and then we pee it all out, so having too much protein can cause serious kidney issues in the long term as well.”
Better Than the Rest
When you’re looking at muscle repair, some forms of protein – known as HBV or ‘high biological value’ – are considered better than plant-based protein because they’re more energy efficient, contain ideal amounts of amino acids and are more readily digested by the body. The best HBV protein-rich foods are generally from animal proteins, so that means meat, eggs, milk and its by-products, such as whey.
If you’re vegetarian and looking for plant-based foods, tofu, legume, lentils and nuts are all great sources of protein, so make sure your diet includes adequate serves of these.
Are Protein Shakes and Bars Useful in our Diet?
Having a protein shake or bar after your weights session can be a great way to get an instant boost, with studies showing that consuming protein immediately after exercise sends it to your muscles more quickly. But don’t overdo it, warns Georgie. Ideally, she says, try to consume protein from real food after a workout if you’re able to. “You have a two hour post-workout window in which you gain the benefits of taking in protein quickly,” she says.
Be kind to your kidneys and don’t overload them with protein, says Georgie: “You’re better off limiting bars or shakes to not more than one or two per day and trying to get most of your protein from real food instead.”
Still not quite sure what you should be eating in terms of a healthy nutritional breakdown? The 12WBT Nutrition Plans are designed to do all the thinking for you.