Proteins and cons
Key may be in when, not how much
These days, it seems you can’t turn a corner without hearing about the latest high protein diet, or stumbling across a product touting its protein content, where once fibre or essential nutrients were the source of such bragging rights. So, how much protein do you really need? And can you get too much? Let’s dig into both questions this week.
HOW MUCH PROTEIN DO I NEED? — THE CONSERVATIVE VIEW
The simple way to figure out how much protein you need is to use what are known as the Recommended dietary Allowances (RdAs). These are the established recommendations that are meant to meet the needs of the vast majority of the population (97.5%, to be exact) each day.
The dRIs are established using what are known as obligatory nitrogen losses — nitrogen being a key component of protein (protein is made up of amino acids, which differ from both carbohydrates and fats in that they contain nitrogen, in addition to the usual carbon, hydrogen, and oxygen), so the dRIs were developed by estimating how much nitrogen our body loses (e.g. through our urine, feces and skin) every day. That amount (about 0.34 grams per kilogram of body weight per day) is then increased to reflect the fact that we don’t use the protein we eat 100% efficiently (bringing it up to 0.6 grams per kilo per day).
From there, something known as a “safety factor” is applied; this is to ensure that people whose needs deviate from the average are accommodated. That brings the recommendation up to 0.75 g/kg/day, which is rounded to 0.8 g/kg/day — and there you have it: The standard protein recommended for most adult Canadians (pregnant women, serious gym-goers and competitive athletes need more) each day. doing a bit of math, that would mean that a 70 kg/154 lb adult would need about 56 grams of protein per day (70 x 0.8 g/kg/day), an amount easily achieved for most people.
HOW MUCH PROTEIN? — NEWER RESEARCH
While the dRI has been in use for years, there is mounting agreement in the scientific community that our optimal protein needs may be higher — perhaps significantly so — than the RdA.
“To me it should never be the RdA, it should be the MdA, the minimum dietary allowance,” McMaster university researcher and protein expert, dr. Stuart Phillips said in an interview. “In other words, if you were doing little to nothing, you were not worrying about the protein mass in your body, you weren’t older, you weren’t growing, you weren’t sick, you weren’t a kid, that might define your protein needs that way.”
At issue is our body’s use of protein to build and maintain lean muscle, the all-important stuff that not only makes us strong, but also has a small, but significant effect on our metabolism (the amount of energy we burn at rest — the more muscle we have, the more calories we burn), as well as protein’s role in promoting satiety, or fullness, which is vital for weight loss. There is mounting evidence, for example, that breaking our protein up throughout the day is better for muscle building, known as muscle protein synthesis. your body is always in a state of both building up and tearing down muscle; we want to prevent the tearing down from exceeding the build-up. The sweet spot seems to be at an intake of about 20 to 30 grams of protein per meal.
In other words, eating about a palm-sized serving of meat is enough protein to get the most out of our muscles, without overdoing i t. For many of us, that means that our breakfast is shy in protein (especially if your breakfast is based on bagels, scones or plain fruit), while our dinners may be giving us more than our body can use at one time.
As we age, we become prone to sarcopenia, or agerelated muscle loss; in other words, we start losing more protein than we gain. Newer research, however, suggests older adults can actually build up protein at about the same rate as younger adults, as long as they get closer to 30 grams of protein per meal.
“For younger adults, I think 20 grams is perfectly adequate,” Phillips said. “For older adults, it might be 3040 grams.” According to this line of thinking, most people would need 30%-70% more than the RdA.
As for the effect of protein on weight, studies such as the OMNI-Heart trial, which examined a higher protein diet that was rich in fruits, vegetables, fibre and derived much of the protein from vegetarian sources, suggests that a slightly higher protein intake can support weight loss, at least in part by acting as an appetite suppressant.
PROTEIN SAFETY
The main concern with too much protein is its effect on kidney function. While those with defined kidney issues (renal insufficiency or failure) need to carefully control their protein intake, the research to date suggests that higher protein intakes seem to be welltolerated. On the other hand, if you are going to try to bump up your protein, especially at breakfast, realize that you need to eat less of something else, or else the needle on the scale can end up going the wrong way. After all, protein foods still contain calories, and overeating any caloriecontaining food can do more harm than good.