Author: Doug Cook, RD MHSc CDE
Protein has a wide range of health benefits including the promotion of healthy bones, preserving muscle mass as we age, increasing a sense of satiety which may be an important ally in healthy weight management.
This same research is now suggesting that we’ve likely underestimated the amount of protein needed to optimize health; an amount that is more than what is currently recommended but still achievable with some minor adjustment to how we build our meals. For most of us, it means spreading our protein intake evenly throughout the day; getting about 30 g in total at each meal.
How much protein do we need?
Dietary protein requirements, or the Recommended Dietary Allowance have traditionally been expressed as an amount based on body weight; 0.8 grams of protein per kilogram of body weight for healthy adults; an amount that prevents overt protein deficiency in 98% of the population. Using a body weight of 73 kg as an example, this works out to 58 g of protein per day. Using this method, a person’s estimated protein requirement, to prevent deficiencies, would vary based on weight; some needing more and some needing less than this 58 g example but the more important question is whether or not this is enough for most people? With 43 g of protein per serving, this BBQ Chicken over Apple Maple Baked Beans is a great source of protein. Recent research suggests that getting 30 g of protein at each meal helps to maintain muscle mass better than eating most of it at one meal, such as dinner for example.
The recommended intake of 0.8 g per kg of body weight was determined using nitrogen balance studies which measures how much total dietary nitrogen from protein was consumed compared to how much was excreted via urine, stool, and sweat. For decades, this was the gold standard for estimating protein needs; however this approach was not without some controversy with respect to accuracy. A main criticism of this technique was that it over-estimated the amount of protein (and therefore nitrogen as well) that people were consuming and underestimated the amount of nitrogen that was lost.
Recently, a new technique to estimate protein requirements has been proposed and validated called the Indicator Amino Acid Oxidation (IAAO) method developed by Ball and Bayle. This method is much more sensitive and accurate at determining both the rate of amino acid oxidation (the amount of protein being used for energy/fuel) and muscle protein synthesis – and the amount of protein needed for muscle tissue growth and repair.
Results from studies using this new method indicate that we’ve likely been underestimating protein requirements by 50% for decades and suggest that the RDA may need to be increased from 0.8 g per kg of body weight to 1.2 g per kg.
How difficult would it be to get more protein?
While the vast majority of Canadians are meeting the current recommended intake of 0.8 g per kg of body weight according the Canadian Community Health Survey, some are not, which may present a challenge if protein recommendations were ever increased. Others, on the other hand, can and are easily eating protein in the 1.2 g per kg range. For anyone who isn’t meeting current recommendations, finding ways to increase the portions of protein-rich foods may be a challenge if incorporating more protein means making changes to how, when, and what they eat
Using the previous example, a person weighing 73 kg would need to eat 58 g of protein from all sources based on current recommendations. If we actually need more protein, as research is suggesting, then that same 73 kg person would need to eat a total of 88 g, or 30 more grams, of protein per day. Try this Chicken Avocado and Black Bean Salad. It’s tasty and chock-full of protein so that you can bump up your protein intake.
While most think of meat, fish and poultry as being synonymous with protein, protein is also found in eggs, dairy such as milk, cheese and yogurt, as well as whole grains, nuts, seeds and pulses (chickpeas, lentils, dried peas and beans). An extra 30 g of protein could be easily achieved by consuming a little more of these foods such as 85 g (3 ounces) of chicken, which provides about 21 g of protein, and 125 mL (½ cup of cooked lentils) which provides 9 g of protein. This Cauliflower, Lentil & Chicken Soup has protein from both chicken and lentils.
Benefits from eating more protein
Current protein recommendations were established to prevent protein deficiency, an amount that’s needed for surviving, but not necessarily thriving. This is because protein has many other roles and benefits including appetite suppression, increased satiety (the feeling of not needing to eat in between meals), preventing muscle breakdown during weight loss, and helping to maintain muscle mass as we age. Timing of protein consumption seems to be as important too; eating adequate amounts; about 25–30 g at each main meal will help to preserve muscle, increased satiety, and provide energy.
For those who already eat enough protein it’s likely that redistributing protein consumption throughout the day is all that’s needed. Most of us eat a protein-light breakfast, a lunch with modest amounts and then a protein-heavy dinner; moving some of that dinner protein earlier in the day to breakfast and lunch is an easy way to ensure that the benefits of protein are maximized. Chicken is a good source of high-quality, inexpensive protein and can be included in breakfast, lunch and dinner. For a ‘to go’ breakfast, try the Grab and Go Breakfast Burrito. Round out the 22 g of high quality protein that this recipe offers with a glass of milk or some yogurt to reach the ideal protein intake of 30 g per meal.
Indicator Amino Acid Oxidation: Concept and Application http://jn.nutrition.org/content/138/2/243.full
Reevaluation of the protein requirement in young men with the indicator amino acid oxidation technique www.ncbi.nlm.nih.gov/pubmed/17921376
Considerations for protein intake in managing weight loss in athletes. (also during energy restriction coupled with exercise) www.ncbi.nlm.nih.gov/m/pubmed/25014731/?i=2&from=exercise,%20nutrition