The truth about protein
by Maureen Tilley, PDt
Protein has a long history of being in the nutrition spotlight from the latest protein supplement to bulk up muscle or improve athletic performance to the newest version of the high protein, low carb weight loss diet. We see these claims everywhere and if it’s not you who has tried it, you certainly know someone who has.
Is there any truth to these protein claims? Are they safe and do the results last? Let’s set the record straight and look at the science, while also gaining a better understanding of its role, how much we need depending on age, health status, goals and how to get maximum benefit from the protein we eat.
It’s common knowledge that protein is essential in muscle building and maintenance but that’s just one of its many roles. It’s also needed for building bones, skin, hair, and nails, as well as, hormone regulation and helps fight infection. The Recommended Daily Allowance (RDA) is 0.8g per kg body weight. Canada’s food guide recommends 10-35 per cent of our calories come from protein, (45-65 per cent carbohydrates, 20-35 per cent fat) approximately 50g/day for the average person on a 2,000-calorie diet.
The protein package
Well-known sources of protein include meats, poultry and seafood, while often overlooked is dairy products and plant-based options such as legumes (beans, lentils), nut and seeds, soy products and quinoa. (Look up Health Canada’s “Nutrient Value of Some Common Foods” for protein in foods). It’s important to look beyond the protein content and consider what else that food has to offer. Legumes are low in fat and high in fibre while, fatty cuts of fresh and processed meats are high in saturated fats (linked to plaque buildup in arteries) and high in nitrates (may be linked to cancers). Protein powder and supplements are an easy and convenient option, but usually lack nutrients like iron and B12 you obtain from food sources. Key message is that all foods fit; but aim to get the majority of your protein from unprocessed, low saturated/transfats and sodium sources.
Can you get too much?
Protein is not stored in the body so should be eaten daily. On the other hand, if we eat more than our body needs, the leftovers are used as energy or stored as fat. Excessive protein intake has been argued to cause kidney damage and decrease bone density but many of these findings were found in rodent studies. Research performed on humans has deemed short-term high protein diets to be safe in healthy adults.
Many experts feel confident that a short-term protein intake 2.0g/kg body weight is safe. Keep in mind; more research is needed to determine if long-term high protein consumption is safe. Even short-term high protein intake can be harmful for individuals with certain health conditions such as kidney disease or kidney stones. Always speak to a healthcare profession prior to increasing your protein.
Aside from protein content itself; certain risks can accompany a high-protein diet. Often when eating a lot of one type of foods, it limits others increasing the risk of nutrient deficiencies—fibre, vitamins and minerals. Protein choice matters and many animal and processed products can increase cardiovascular and cancer risk while plant-based options can lower it.
Most Canadians get a large amount of protein at dinner, moderate at lunch, while breakfast is lacking. Research has shown that spacing of protein may be equally, if not more important than total daily intake. It’s thought the body utilizes small portions more efficiently than large doses at once. We know the importance of eating breakfast and adding protein in the morning further enhances the benefits, helping increase fullness at meals and throughout the day, decrease cravings for high sugar and fat foods and help reducing blood sugars. It can be challenging to get enough at breakfast, as most traditional (healthier) breakfast proteins tend to be lower in protein (6g per large egg, 4g per 100g yogurt). Add a protein boost to hot cereals with egg white, seeds/nuts, Greek yogurt, peanut butter, or cooked red lentils (you won’t even taste them!). Make an omelet and add leftover chicken or black beans. Replace milk with Greek yogurt in cereal, add it to a smoothie, on top of pancakes or a yogurt parfait. Toast can be topped with cottage cheese, ricotta or fish (sardines, tuna, salmon) and sliced avocado and tomato. You don’t have to stick with traditional fares either; try a sandwich or leftovers.
Aging population and muscle mass
We start to gradually lose muscle mass in our 30s and more progressively declines in our 50s with a 30-50 per cent loss by our 80s. Loss of muscle leads to loss of strength and mobility and increased risk of fractures and illness. Muscle depletion can be slowed by exercise and nutrition. Despite Health Canada’s RDA recommendations for all adults, research from the International PROT-AGE Study Group and European Society for Clinical Nutrition and Metabolism (ESPEN) found a daily protein intake of 1-1.2g/kg provided better muscle preservation in adults older than 65 years. Higher intake (1.2-2.0g/kg) is recommended for individuals with certain chronic and acute illnesses/injuries. There may even be benefit in increasing protein recommendations in 30-40s when muscle decline begins. More research is needed, but it’s safe for healthy seniors to aim for the higher protein intake.
Animal vs plant
Dietitians of Canada state vegetarian and vegan eating patterns are healthy and nutritionally adequate ways of eating; it may just require a littler more organization. It can also be nutritionally balanced for those with higher protein needs such as athletes. Studies have shown that plant-based protein provide equal exercise capacity as omnivore-based eating. Most animal products are higher in protein per serving compared to plant-based proteins but we can still get enough if adding at meals and snacks.
Protein is made up of various strands of amino acids that are needed to form complete proteins. Animal sources (as well as soy and quinoa) contain complete proteins, while most plant-based proteins are incomplete; amino acids need to come from other foods like whole grain bread and baked beans. We used to believe plant based proteins had to be paired with particular foods at each meal, but we now know that as long as a variety of foods are eaten throughout the day, then complete proteins can be formed. Research shows individuals who eat more plant-based foods have decreased risk of heart disease, diabetes, certain cancers and hypertension. It’s also better for the environment as production of plant-based products uses far less resources than the raising of most livestock.
Many popular diets such as Atkins and paleo focus on high protein and low carbohydrate intake. Studies have found that high protein can lead to weight loss but the actual mechanism is not well understood. There are several hypotheses including: protein is more filling, leading to decreased caloric intake; it suppresses our hunger hormone ghrelin; and protein increases the metabolism. Perhaps it’s simply the fact that cutting out food groups and/or watching what you’re eating automatically leads to a decrease in calories. Most weight loss diets, whether low carb, counting points, high fat, or high protein, lead to weight loss. The most challenging part is trying to maintain it over the long term and most people regain the weight they’ve lost. So what’s the solution?
The best approach is an individual approach. Learn to feed your body based on what it needs (mind and body) and not dictated by diets or the scale. It’s not glamorous and requires adjusting weight loss expectations but it frees you from a lifetime of diet cycling and more likely to lead to better mental and overall health.