Anyone that knows me, or that has ever come to my sessions knows that one of my favorite areas of nutrition is protein. Why? Mainly because it is a very powerful nutrient that has the ability to signal the body to build new structures and tissues in the body, including muscle, amongst many other benefits.
Let’s look at 3 benefits protein has for muscle growth, and weight loss you probably did not even know:
Protein is a signaling nutrient. It basically give signals to cells in the body to do something for them and it is usually related to producing something new (I.e. new muscle fibers, new hormones, new blood cells, etc)
Protein is a high thermogenic nutrient. Wait, did you say thermogenic? Isn’t that the scientific term for “fat burning”? Not quite. Proteins are very complex molecules and they need to be properly digested to enter the blood stream. That process to digest a protein is very energy-depriving. In other words it requires a lot more calories to process them as opposed to carbs or fats. So I am saying that consuming a higher protein diet usually allows you to burn more calories daily.
Protein is an appetite suppressant. WHAT?? Proteins usually promotes satiety, meaning you feel full longer. It helps you curve hunger, therefore preventing overeating.
The topic of protein in Academia has gained a lot of traction in the past 20 years as a very hot topic for research. So much, that the general protein recommendations for adults set by the USDA (1) at 0.8g/Kg (are you kidding me?) are now being contested and criticized for being too low and not enough to support maintenance and integrity of lean body mass. The American diet however, tends to have a protein intake way higher than the recommendation anyways. Did you know a NY Strip contains over 100 grams of protein? For an average 165 lbs. male, that is 60% above the USDA daily recommendations IN ONE MEAL. Is that bad? I mean you are telling me that we can have more right? Well yes, but turns out that more important than the amount, is how you split that protein in the day, a term called PROTEIN TIMING.
Let me explain this concept with a graph. I am sure you are all aware of the terms catabolism (break things down, break down sugar for energy, break down muscle, etc) vs. anabolism (build things up AKA build muscle). The undulating curves represent protein synthesis.
Adapted from Paddon-Jones and Rasmussen (2009)
We wake up in the morning in a catabolic state (fasted), consume a breakfast rich in high quality protein (let’s say some eggs), and stimulate muscle protein synthesis or MPS (the curve raises and we enter anabolism, YAY!). Now we have to clarify, that protein does not have to be consumed every 1-2 hours, but more like 3-4 to allow the curve to come down – In other words, it is better to turn on the switch to muscle growth repeatedly throughout the day, rather than providing a constant source of protein that may be used as energy in some cases or stored. This is even proven by this awesome research article in which they did the following:
– They took 24 dudes and separate them into three groups. Each group was randomly assigned to one out of three treatments: a PULSE protein feeding grop (8×10 g of whey protein every 1.5 hours), an INTERMITTENT protein feeding group (4×20 g of whey every 4 hours), and BOLUS feeding group ( 2×40 g of whey protein every 6 hours). All these groups exercised (lifted weights) prior to the first feeding. The 12 hours following this (recovery period) they fed them with the treatments.. If you noticed, they all received 80 grams of whey protein separated in different time intervals and different amounts. Guess what the results where? YEAP the INTERMITTENT feeding had the greatest MPS (muscle growth) in the recovery when compared with the other two treatments (2).
Let’s translate this into the average American diet. Think about the average meal schedule of the average Joe (Check out the graph)
Breakfast: Bagels and OJ (No protein)
Lunch: A turkey wrap, a sandwich, or some pasta (15-20 grams if we are lucky)
Dinner: 12 oz NY Strip with vegetable and a baked potato (80+ grams of protein)
If the average American would simply time their protein better, drastic changes would be seen in weight. Let’s take it a step further, and break down the protein to its most important component responsible for muscle growth… LEUCINE!!!!
An important consideration when examining protein is the LEUCINE content of protein foods – Leucine is a Branched Chain Amino acid (BCAA ) and is believed to be the key amino acid in signaling upregulation of mTOR (the molecule that orchestrates all protein metabolism). We need at least 2.5 g of Leucine to activate this switch (and raise the curve to anabolism – see graph )
Leucine Content of some foods:
1 scoop of Whey Protein Isolate = 2.5-3.5 g Leucine typically
4 cups of skim milk = ~2.5 g Leucine
4 oz of meat = ~2.5 g Leucine
13 sliced of bread = ~2.5 g leucine (WOW! – this is just to put things into perspective. Bread is not considered a protein source)
1 cup of Greek yogurt = ~2.5 g Leucine
Ok cool. You get it, you need Leucine, but how much protein do you need per feed then?
If you see the first graph there is a red-dotted line that represents leucine threshold. The blue dotted line represents leucine saturation. So, 15-20 grams of high-quality high-leucine proteins will flip the switch and stimulate MPS, but 25-30g will reach the leucine saturation stimulating MPS for even longer. Now, more than 30-40 g is not more beneficial from the anabolic perspective. If you are on a high calorie diet, more than 40 g of protein may be necessary as you need the extra calories, particularly if you are following a macro counting diet. But what is not true is that more protein = more protein synthesis.
The takeaway from this post is you must time your protein to allow MPS to start multiple times/day. We know that resistance training stimulate protein synthesis 24 and up to 72 hours post training, and protein in food boosts that effect. We definetely need more protein than the recommendations set by the USDA, but choosing the right quality and the right time appears to be what matters the most.