Are you confused about what you should be eating in order to meet your goals? You’re not alone.
There’s a great deal about nutrition that we know. But there’s also a good deal of information we are still clarifying. One of the areas of nutrition that remains riddled with myths and misconceptions is protein. This post is aimed at helping you understand how much you need, once and for all.
The protein we consume (from both plant and animal sources) is digested into individual amino acids before being absorbed into our bloodstream as individual amino acids. When we have a sufficient “pool” of amino acids in our system, our body can build any tissue or structure we need.
While both plant and animal foods contribute amino acids when we eat them, the richest source of essential amino acids (and all amino acids for that matter) are animal-based foods such as eggs, dairy, meat, poultry and seafood.
Animal sources of protein contain high concentrations of all necessary amino acids, little-to-no carbohydrate and varying amounts of fat. Plant sources of protein contain mostly carbohydrates and only modest amounts of “incomplete” proteins, which makes it difficult to meet protein and amino acids needs solely from plants.
There are twenty amino acids the human body uses to build its cells, organs, enzymes, muscles and hormones. If we don’t consume enough amino acids, our body will “steal” them from our own tissues by breaking them down (the first tissues to be sacrificed are believed to be skeletal muscle).
Ten of the twenty amino acids can be made within the body by converting other available amino acids. The other ten must be consumed regularly and sufficiently in our diet to maintain our health and function. These (which must be consumed) are called “essential” amino acids, as in it is essential for us to eat enough of them daily.
It would be extremely difficult to try to manage or track your intake of all twenty amino acids; in fact, there aren’t even established Dietary Reference Intakes for each individual amino acid[i]. Thus, total dietary protein intake is used as the overarching category and it’s assumed the protein eaten supplies all twenty amino acids sufficiently.
That brings us to the question “How much is enough?” It just so happens that “enough” is a moving target, depending on which result you’re looking for.
Protein needs are expressed in terms of how many grams of protein needed per pound or per kilogram of body weight. The Recommended Dietary Allowance for adult protein intake is 0.8g/kg/day (0.36g/lb/day).
It’s important to note this protein recommendation (RDA) is based on the minimal amount needed to maintain positive nitrogen balance (i.e. avoid deficiency). It’s not a protein intake level that promotes optimal health or function [ii].
That means the protein recommendations most dietitians and health professionals use are literally the bare minimum to stay alive, not thrive. In fact, the standard recommendation of 0.8g/kg/day is probably woefully inadequate.
If you’re physically active at all, you need more protein compared to someone like you who doesn’t exercise.
If you’re dieting or following a reduced calorie plan, you need more protein than someone who isn’t cutting calories.
If you have (or want) a large amount of muscle mass, you need more protein than someone who has (or wants) less muscle.
If you’re middle-aged or older or are dealing with any degree of insulin resistance, you need more protein than younger, healthier people.
As we age, or if we are dealing with obesity and/or insulin resistance, the amount of protein required to stimulate muscle protein synthesis increases dramatically [iii].
In at least one study comparing post-exercise muscle protein synthesis in younger and older adults, the older adults had the best muscle repair response with 40g of whey protein, post exercise. The younger subjects achieved maximal muscle protein synthesis with half that amount [iv].
During an energy deficit, (i.e. if dieting and/or burning additional calories exercising) consuming twice the amount of currently recommended dietary protein measurably protects fat-free (lean) mass and promotes the loss of body fat during short term weight loss (up to 3 months) [v].
There are a few reasons why increased protein helps in this scenario. First, the thermic effect of eating protein is much higher than that of carbs or fat. In other words, your body spends a lot of extra calories just digesting protein. The energy spent digesting actually raises your metabolic rate enough to measure [vi].
Second, protein has a high satiety factor, which means it helps you feel full or satisfied for a long time after each meal, which helps with controlling overall energy intake. In fact, in weight loss studies where some subjects are assigned a higher proportion of their calories from protein, they seem to spontaneously eat fewer calories than others assigned lower protein plans [vii].
That means if you aim for 1.6g/kg/day (0.72g/lb/day) instead of 0.8g/kg/day when trying to lose weight or fat, you’ll be more likely to maintain or gain lean, healthy tissue along the way, and it will be easier to manage your appetite.
Even if you’re not trying to lose weight, you may want to double the RDA for protein too. The International Society of Sports Nutrition and other researchers suggest that athletes may get the best training response when daily protein intake is 1.4 – 2.0g/kg/day (for a 170-pound person, that’s 108 -155 grams per day) [viii], [ix].
To make it easy for you, a more suitable amount of protein can be estimated easily: aim for 1 gram of protein per pound of goal body weight per day. If you currently weigh 200 pounds, but you want to be 160 pounds, aim for 160 grams of protein per day. If you are currently 200 pounds and want to be 225 pounds, eat 225 grams of protein per day.
How much food is that?
Let’s use 160 grams as our example for a daily protein intake goal. For simplicity, I like to suggest breaking up your protein across 3 to 4 meals each day. In this case, four meals that each supply 40 grams would be a good start (or you could aim for three meals of 45 grams protein each, plus one snack that includes 25 grams of protein).
Protein rich foods (eggs, meat, poultry, fish, seafood, dairy) are usually measured in ounces, not grams, so choosing your protein portion can be a bit tricky. One ounce actually weighs 28 grams, but one ounce of meat/poultry/fish contains about 6 or 7 grams of actual protein.
For our example day of 160 grams of protein, that means we’d aim to consume four meals that each have 6-7 ounces of protein-rich foods. Six ounces of protein-rich food contains roughly 40 grams of actual protein and looks like one to two palm-sized portions (depending on the size of your hands). Imagine how satisfied you’d feel if you ate three eggs and three ounces of ground beef with veggies for breakfast!
Considering that meals at many fast-casual restaurants only serve up 2-4 ounces of protein for their menu items, you should probably be ordering extra or even “double” protein if you’re eating out.
Or you could make up for lower protein meals by eating a very high protein meal at least once a day. At least one study suggests that you can get the same overall benefits of higher protein intake if you consume one large meal per day. Subjects who ate 80% of their total daily protein need at one meal appeared to have the most “anabolic” response to protein [x].
For our 160 grams per day example, that would mean one meal containing 128 grams of protein might be just as good, if not better for muscle maintenance than spreading out protein evenly, suggesting there isn’t an “upper limit” at each meal as many people believe.
Although this sounds like a lot of food, rest assured your body will probably benefit from the ample supply of amino acids, whether the benefit is muscle growth or maintenance, appetite and hunger control or metabolic boost. And contrary to many myths, this moderately high protein approach will not negatively impact your bones or kidneys (unless you have pre-existing kidney damage) [xi],[xii].
Can you get too much protein?
It’s certainly possible to overeat protein. However, because it’s difficult for our body to convert excess protein to fat, it’s not likely to contribute to weight or fat gain.
For example, researchers have investigated what happens with very high protein intakes in resistance training individuals, and the results are interesting. When resistance-trained subjects were fed five times the RDA, (4.4g/kg/day) which added about 800 extra calories per day, they gained no fat. Their kidneys were fine and in fact, they didn’t gain any weight at all [xiii].
Of course, even though nothing bad happened when subjects ate 800 extra calories of protein at five times the RDA, doing so is definitely excessive because there was no apparent benefit compared to the group consuming just above 2-times the RDA.
Excess amino acids are rather easily converted into glucose that your body uses to produce energy. But in doing so, your liver creates a great deal of nitrogen-containing waste that your kidneys need to flush out of your system. If you’re eating aggressive amounts of protein, you’ll need to drink plenty of water, and even then you may notice that your sweat and urine may have a slight ammonia-like odor.
In short, eating higher amounts of protein has a number of positives but there’s definitely a point of diminishing benefits somewhere near twice the RDA of 0.8g/kg/day.
Many of my clients (and myself included) find it challenging to always achieve protein needs with whole food alone, so protein powders are a staple in our strategy to meet our nutritional needs. They are convenient and offer easily digestible sources of all the amino acids our bodies need to build and maintain healthy, lean bodies.
In health, Paul Kriegler, Registered Dietitian and Life Time – Nutrition Program Development Manager.