Protein: From plate to muscles Part 2

If you’ve been following this series on protein, by now you are ready for some actionable items. In this week’s post we’ll cover how we can optimize protein synthesis (aka build muscle) and maximize recovery.

Since the topic can be overwhelming, here’s a recap of Part 1 so you know where we’re headed next:

The Various Fates of Protein

• Ingested proteins are broken down primarily into individual amino acids, the gut selectively transports these
• About 50% of ingested amino acids are absorbed by the gut; almost all glutamine is absorbed by the gut
• Stored amino acids in the gut are used to buffer blood amino acid levels between meals and at night
• Amino acids enter the liver through the portal vein
• Over half of these amino acids in the liver are oxidized for energy or used to synthesize new proteins
• The remaining 10% of the total ingested amino acids can now enter the bloodstream - most of these are the Branched Chain Amino Acids (BCAA)
• Amino acids entering the bloodstream from dietary sources pool together with amino acids released from tissue to form the "free amino acid pool"
• Only very small amounts of amino acids form the pool at any one time: about 100g total with only about 5g of that being in the bloodstream
• You can induce larger rises in blood amino acid concentrations by consuming whey or amino acid supplements but amino acid oxidation (use for energy) also increases
• Most protein/amino acids ingested from diet are used for various repair by organs, burned for energy or used to create new proteins. Only a very small amount are actually used for muscle growth and repair.
• Ingesting protein in amounts over the optimal needs results in more protein being simply burned for energy, you cannot "force" muscle growth through more protein

Protein Turnover

Nope, it’s not a meat-filled version of an apple turnover, sorry to let you down. Instead, protein turnover is the balance of protein synthesis and protein breakdown.

While you have the same relative muscle mass day to day, you are constantly going through protein breakdown and synthesis. Amino acids from muscle and other tissue are broken down and released into the bloodstream to be (mostly) absorbed by other tissues in the body.

Once in the bloodstream, there is no difference between amino acids from various sources. For an amino acid like valine, for example, there is no difference in the bloodstream whether it came from chicken or breakdown of muscle tissue. Once it enters the amino acid pool, there is no distinguishing where individual amino acids come from.

In terms of total protein turnover each day, someone around 175lbs or so will probably turnover about 300g protein. Clearly that is more than most people eat and that is perfectly fine, as much of that 300g comes from various tissues being broken down; but don’t fret, most of those amino acids are absorbed right back in other tissue.

Tipping the Scales in Your Favor

It’s important to note that protein turnover is pretty much always happening, it’s not something you want to fight or stop. We need proteins to be broken down so non-functioning or misfolded protein do not accumulate in the body, we also want breakdown so there are always free amino acids available for tissues that need it. If not, you’d only be able to repair muscular tissue when you eat.

We can’t do too many things to stop muscle protein breakdown, nor do we really want to. Small spikes in insulin are sufficient to lower protein breakdown and this works in tandem with a meal containing protein. Insulin goes up, protein breakdown reduces, and because of the ingested protein, protein synthesis goes up!

To tip the scales in the favor of muscle growth, we’re much better off at focusing on synthesis rather than trying to stop the breakdown.

Training

When you lift weights, especially with sufficient intensity, you induce a “net anabolic” effect on the body. Following a resistance training session, both muscle protein synthesis and breakdown go up. Since training is a stressor, proteins are broken down but since training also increased or sensitivity to synthesis, with proper amounts of protein, we shift things in our favor.

It’s kind of like spending $5 to make $10. In terms of real muscle mass accumulation, it’s probably more like spending $5 to make $5.50 and that’s simply because muscle mass accumulation is a slow process. Either way, training allows you to accumulate new protein and build larger muscles so if you are making progress, you are most likely doing things as fast as they will happen.

Eating

As mentioned previously, eating a meal that contains protein will stimulate insulin (which slows or halts protein breakdown) and the amino acids will stimulate muscle protein synthesis.

Clearly you can’t just eat truckloads of protein and gain muscle mass. While eating a meal does stimulate protein synthesis, you won’t end up “storing” more (aka gain muscle) unless you have a signal to do so.

Training is that signal which is why it’s so imperative that you combine proper resistance training with optimal protein intake. That combination is more important for muscle mass gains than worrying about carb/fat combos, supplements or meal timing.

If you consume more protein than usual during the day, you will store some of it in the gut. As mentioned before, when protein intake goes up, so does protein oxidation. Unless you have the signal from resistance training telling the body to store more protein in the muscles, you won’t gain muscle mass. Instead, you’ll simply store more amino acids in the gut after your large protein meals and you’ll breakdown and use/burn more during the night while you sleep.

Again, force feeding protein simply means increased amounts of protein used for fuel. You can overeat protein and be perfectly fine and healthy of course; some people find increased protein to be more satiating while dieting or they simply prefer protein-rich foods. There is some speculation that increased protein oxidation contributes to an “anabolic drive” in the body, which means that even though you might be burning more protein for energy, the oxidation of that protein keeps you In a more complete anabolic state.

Lastly, protein is metabolically costly to digest and absorb so eating more protein means expending more energy which means more total calories burned. If you eat 200g protein per day, that’s 800 calories from protein. 30% of that used in protein digestion/absorption is about 240 calories.

If you bumped protein intake to 300g per day, the amount you burn in digestion/absorption increases to 360 calories. For some people, that extra 120 calories burned daily might be worth it, especially when combined with how satiating protein is while dieting. Just remember, it’s not necessary in the least, it’s just a tactic.

Practicality

Moderate sized meals containing protein (30-50g) are going to shift the body into an anabolic state for up to 5 hours, possibly even more for very large meals or slow digesting proteins like casein. However, 5 hours is a good safe mark so depending on meal size, you most likely don’t want to go longer than 5 hours without eating.

If meals are too small, not only do you run the risk of providing insufficient amino acids but the muscles can become desensitized to amino acids; eating more frequently than every 3 hours should also be avoided. Obviously a snack in between meals is OK but there is no reason to try to consume 6-8 small meals a day and run the risk of amino acid desensitization.

Eating every 3-5 hours (I often recommend larger and less frequent meals to help with satiety) is a good choice. Then divide your total protein intake up among however many meals that ends up being for you.

For most, 3-5 meals spaced 3-5 hours apart works pretty well.

Protein Intake

You want to make sure your total protein needs are met. Accurate protein needs are based off of lean tissue, exercise and activity status and goals. However, determining lean tissue in most people can be a guessing game so if someone is relatively lean, we can go off of body weight.  If someone is considerably overweight, just slide their intake down the scale until you reach a reasonable number that they can hit

.

 For strength training individuals, eating between 1.8 to 2.2 grams per kilogram (or 0.8 to 1 gram per pound) is ideal. Eating high quality and complete proteins that meet these windows will also meet the leucine threshold and cover all bases!

For an active athlete with lower body-fat, 1 gram per pound is pretty ideal whereas someone who might be 75lbs overweight probably needs to be closer to 0.6 to 0.8g/lb.

While total daily protein is the most important in terms of losing or gaining muscle, the meals that book-end your day are also quite important. If you have slept 8 hours you've been fasting for at least that long. When you wake up, protein synthesis is at an extreme low and a high-protein meal rich in leucine helps stimulate mTor and reverse the catabolic process of fasting. Likewise, before bed, a complete and slow-digesting protein can provide amino acids to help reduce catabolism (or muscle breakdown) while you sleep. Optimizing both of those meals can help push muscle growth even further and ensure you are recovering optimally.