Walk down the health food aisle of a regular supermarket and you’ll see shelves groaning under the weight of protein bars, balls and powders. Even service stations are cashing in on the rocketing demand for extra protein.
Bodybuilders initially drove the market for protein supplements, but it now seems that everyone who exercises believes that adding protein to their diet is a quick way to both build muscle and lose weight. The market for protein supplements has grown in Australia by 14 per cent every year from 2009 to 2014, with little sign of abating.
How the body uses protein
From muscle growth and tissue repair to an effective immune system, practically every body system requires protein. Eat a steak, a handful of nuts, or an omelette, and your body will break down the protein to amino acids, then re-assemble them as needed.
If you have a protein deficiency, your body will break down its own protein to make essential new proteins. Because your muscles contain a large amount of protein, they are the first area targeted, which is why muscle wasting is commonly seen in severely malnourished people.
“If you eat more protein without increasing your exercise, your body simply converts some of it to energy, storing the excess as fat.”
Protein to muscle
You can’t build muscle without adequate protein, as protein provides the amino acids needed for new muscle growth and repair. That said, it’s impossible to eat your way to well-toned muscles. You need to combine protein with strength training to get the effect you want.
If you eat more protein without increasing your exercise, your body simply converts some of it to energy, storing the excess as fat.
So more exercise + more protein equals bigger muscles?
That’s the belief that’s fuelling the current protein craze, says nutrition research scientist Dr Tim Crowe. But taking extra protein in supplement form delivers few benefits.
“Taken together, strength training and sufficient protein will stimulate new muscle protein synthesis,” he explains on his blog, Thinking Nutrition.
“Note that the keyword here is sufficient, because this is where protein supplement marketers like to extend to ‘the more the better’.”
For athletes, a protein intake of 1.2 grams to 1.7 grams per kilogram of body weight is recommended. The top end of this range is for elite athletes. Recreational athletes (that’s most of us who work out) need have no more than 0.8 to 1.2 grams/kilogram of body weight. Most men and women in Australia easily get this amount through diet alone.
Too much of a good thing?
Protein drinks can contain up to three times as much protein as two eggs, while some protein snack bars can pack in as much as found in a 200g steak. These ‘snacks’ give you more protein than most meals. Many experts see consuming protein supplements as expensive but harmless, but others caution against what they see as a relatively new invention.
“It’s an experiment,” says Dr John E Swartzberg, chairman of the editorial board of the University of California, Berkeley, Wellness letter. “No one can tell you the long-term effects, or what the results are going to be in people’s bodies 10 or 15 years later.”
What we already know is that a high protein diet increases the amount of calcium excreted, risking bone health in the long term. High protein intakes also put added pressure on your kidneys and can accelerate the progression of any pre-existing kidney disease. Then there’s the fact that filling up on too much protein is likely to be at the cost of other vital foods, like whole grains, fats, fruit and vegetables. Most of us get plenty of protein, but many are lacking in these healthy diet basics.
A number of studies have shown a link between diets high in animal-derived protein and diabetes. And some experts even warn of a possible increased risk of cancer with excessive protein. According to Dr Walter Willett, chairman of the department of nutrition at the Harvard T H Chan School of Public Health, animal protein tends to make cells multiply faster. While this is good early in life, later on this is a fundamental process that increases cancer risk.
For every expert with a warning, there’s another quick to dismiss the fears, and plenty of nutritionists support the notion of an increase in protein. But protein from ‘real’ food beats supplements hands down, as food comes with added nutrients that can’t be found in a bar.
Most protein supplements contain whey, a natural milk protein. The first reason is convenience. Whey is a waste product from cheese manufacturing, so is relatively inexpensive. It also happens to have a stronger effect on muscle growth than other proteins, because it contains plenty a specific essential amino acid called leucine.
Of course whey doesn’t need to come in powdered form, as you’ll find in naturally in milk and yoghurt. In fact one of the best post-workout drinks supported by science is chocolate milk.
Chocolate milk (or any sweetened milk) contains a good mix of carbohydrates, says Associate Professor Tim Crowe. Carbs will stimulate insulin release that helps transport glucose into your muscle, where it becomes glycogen. Insulin also stimulates muscle protein repair and growth.
Chocolate milk also contains high-quality whey and casein protein, plus contributes to post-exercise re-hydration. It also offers a host of other nutrients including electrolytes, calcium, magnesium and vitamins A and B. All for a fraction of the cost of a commercial post workout drink.
Which foods contain protein?
Each of the following servings provides approximately 10g of protein.
2 small eggs
30g (2 slices) cheese
1 cup (250ml) low fat or regular milk
35g lean beef, lamb or pork (cooked)
40g lean chicken
50g canned tuna or salmon
200g natural yoghurt
4 slices (120g) wholemeal bread
3 cups (90g) wholegrain cereal
2 cups (330g) cooked pasta
3 cups (400g) cooked rice
¾ cup (150g) lentils or beans
200g baked beans
60g nuts or seeds
300ml soy milk