Canada AM's nutrition expert Leslie Beck provides answers to common questions about the pros and cons of protein.
Which are the healthiest high-protein foods?
Protein-rich foods include meat, poultry, eggs, milk, yogurt, cheese, dairy, legumes, lentils, tofu, and soy products. These foods supply amino acids, the building blocks used for muscle growth and repair. But your body also relies on protein to make hormones, enzymes and immune compounds. In fact, a diet that's chronically low in protein weakens your immune system and increases the likelihood of catching colds and the flu.
We've all heard that more protein means stronger, bigger muscles. Is this true?
Not necessarily. It is true that people who exercise regularly need more protein than sedentary people. It's needed to help muscles recover from exercise and support muscle building.
Sedentary individuals require 0.8 grams of protein per kilogram body weight per day. For a 190-pound (86 kg) male, this translates into roughly 69 grams of protein, an amount equivalent to 7 ounces (210 grams) of chicken and 2.5 cups (625 ml) of milk or soy beverage.
Studies suggest that endurance athletes like marathon runners need to consume 1.2 grams of protein per kilogram of body weight per day. It's recommended that strength athletes consume 1.2 to 1.7 grams of protein per kilogram body weight per day.
But, getting more protein than you need for exercise won't help you build bigger muscles. In some cases, those extra calories can spell unwanted weight gain. There is a limit to the rate at which protein can be synthesized into muscle. Unlike carbohydrates and fat, the body can't store protein. The excess that you eat will either be burned for energy or, if you're getting the calories you need, it will be stored as fat.
What about protein powders? Are they necessary?
Some people do need the help of protein shakes to meet their daily requirements. Low calorie dieters, vegetarians, haphazard eaters and those who train very heavily may benefit from a protein supplement. If you do use protein supplements, timing is important. You'll build muscle more effectively if you consume protein within one hour of strength training.
According to a study from McMaster University in Hamilton, Ontario, the optimal dose is 20 grams of protein to maximize muscle growth – an amount found in 3 ounces of meat, chicken or fish, 6 egg whites, or 1 scoop of many brands of protein powders. It's also important to consume your post workout protein with carbohydrates (i.e. a fruit smoothie with protein powder or a tuna sandwich). Ingesting carbohydrates triggers an increase in insulin, which helps delivers those amino acids to muscle cells.
What is the difference between the protein powders you can buy?
Whey protein. The most heavily marketed protein supplement is whey, a by-product of cheese making. Whey protein generally contains a higher amount of essential amino acids – which your body can't make on its own – than other protein sources. It also contains proteins that may help maintain immune function during intense training periods.
When choosing a product, look for one that's free of artificial flavours and sweeteners. Avoid brands that contain excess sugar in the form of fructose, dextrose and maltodextrin. Pure whey protein powder shouldn't have more than 2 grams of sugar per 30 grams of protein. Avoid spending extra money on products with added ingredients touted to maximize performance like creatine, growth peptides and glutamine. In most cases there's little evidence to show they help and even if they do, the amount added is usually too small to provide a benefit.
Soy protein. Soy protein powder is an alternative for vegetarians. Like whey, soy protein also contains all of the essential amino acids that the body gets from food. Studies suggest that soy protein may have benefits that extend beyond muscle repair. A regular intake of soy protein may help manage type 2 diabetes, prevent diabetic nerve complications, increase bone density and lower LDL cholesterol. (If you're a woman at high risk for breast cancer, avoid using soy protein powders.)
Whole plant protein powders. Derived from seeds of the hemp plant, hemp protein also supplies all essential amino acids. While it contains less protein per serving than soy, hemp protein is not refined. It also delivers essential fatty acids and fibre. It can be mixed into juices, smoothies and protein shakes and added to baked good recipes. Vega Complete Whole Food Optimizer blends whole hemp, rice and pea proteins to boost the essential amino acid and fibre content.
