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Second Thoughts on Protein

Best Amount of Protein is __________________???

Some time ago I wrote an article about the importance of avoiding sarcopenia as one ages  in which I stressed the importance of consuming enough protein, perhaps more than you are regularly eating. I suggested that you eat thirty grams of protein, three times a day.

While it is of utmost importance that you avoid sarcopenia—no change there—it is possible that for some people, the fairly routine guidelines of three-times-30 might actually be too much protein. In the popular press you’ll see high protein diets disparaged because of the risk of kidney damage, but that’s not what I’m talking about as that’s an almost ridiculous contention. It takes loads and loads of excessive protein, and probably pre-existing renal disease, for high amounts of protein to cause any reduction of kidney function. It’s a false issue.

The true issue, though, concerns quite normal amounts of protein, such as the three-times-30 grams as recommended in my earlier article. That amount has been agreed upon by many to help reverse the natural-with-aging trend of muscle wasting known as sarcopenia. As we age our muscles tend to get smaller and weaker, but we can stop and even reverse that trend if we eat “enough” protein and give our muscles “enough” stress to yield the desired result of muscles strong enough to avert any decline into frailty.

What is Enough Protein?

Ahah, here is the question, because it might be less than what I mentioned before, but that depends on your goals.

If you’re young (under 40) and aiming to build muscle, get in shape, lose some body fat, most fitness experts would recommend as much as 0.5-1.0 or more grams of protein per pound of body weight. So for 160 pound person, that would mean 80-160 grams of protein.

Even if you’re eating  a steak, the entire “weight” of the steak isn’t protein. You can look up the amount of protein in your food on the Nutritional Data base here or you can use this mnemonic from Men’s Fitness. Remember the numbers 1, 5, 10, 15, and 25 for the grams of protein in 1: a serving of fruit or vegetables, 5 for one egg or one handful of nuts, 10 for a cup of milk or yogurt, 15 for a cup of beans or ½ cup of cottage cheese and 25 for a 3-4 ounce serving of meat.

So the generally recommended 90 grams of protein for elders to maintain muscle is within that range, at the lower end. But elders aren’t below 40. Once we're over the age of 40 there are some hazards with keeping protein levels high. I credit Dr. Ron Rosedale for enumerating these at our recent meeting of Physicians and Ancestral Health in Miami. You can read more about his thoughts on his website here.

Dr. Rosedale’s advice is that with age, you calculate your protein requirement quite differently.

  1. Figure your lean body weight. (Think of yourself at the low end of your ideal weight scale, take 15% off of that. So if you’re 160 pounds but would like to be 140, think of your lean body weight as about 120.)
  2. Divide that weight by 2.2 to get your weight in kg: 120 lbs. = 54 kg.
  3. Your ideal intake of protein in grams is half to three-quarters your lean body mass in kilograms, or the much lower amount of  27-41 grams of protein.

That's a lot less protein: ideal for WHAT exactly?

That’s a lot less protein than the 90 grams you get if you eat 30 grams three times a day! 90 grams of protein will indeed make it a bit easier for you to maintain and gain muscle mass, although the MOST IMPORTANT PART is described below. Back to protein, though: yes, 90 grams may be ideal if your only consideration is avoiding frailty and maintaining your muscle mass.

If you are also concerned about avoiding cancer, avoiding metabolic syndrome, and just plain living longer, you might want to reduce that protein intake.

High-ish levels of protein thwart our longevity goals via at least three closely related effects:

  1. Lower IGF-1 levels. Protein consumption is the main determinant of our circulating levels of IGF-1 (Insulin-like Growth Factor-1), a hormone that acts like insulin in many ways: helps lower blood sugar and build muscle among them. But it also is a growth factor and, well, over the age of 40 not much should be growing but brain cells. What specifically should not be growing is little cancer cells: we want our bodies to see them, stop them, and throw them out, not encourage them. Thus, we’re better off with lowish levels of IGF-1.
  2. Keep mTOR lowish. mTOR is a protein in our body that also, in its two forms mTOR1 and mTOR2, regulates cell growth or clean-up as well as interacting with IGF-1. In the setting of lots of carbs OR lots of amino acids from protein, mTOR is increased and can turn off “autophagy” which is the clean-up part of cell growth, where our body might see a damaged cell (takes up too much energy) or a pre-cancerous one, and turns it off.  So our lifespan is likely to increase if we keep mTOR levels on the lowish side.
  3. Burn fat skillfully. Although once out of infancy, most of us rely on the sugar in our bloodstream for fuel, we would be better off if we had the flexibility to switch from sugar right after a meal, to burning our ample fat stores when we’re a couple hours out. Lacking flexibility sets us up for “hypoglycemia” (weak, faint, anxious, sweaty, and MUST EAT SOMETHING.) On the other hand, if we have metabolic flexibility, we can just turn off our sugar-seeking cells and turn to burning fat instead. We can exist for days, weeks (and some of us months) with no problem, relying on our stored fat cells.

We all know that we can get very hungry when we skip a meal. If that’s true for you, that is not a good sign about your metabolic flexibility!  It would be good to actually give yourself some practice. Eat decent-sized meals and develop the ability to go 4-6 hours between meals. Once you can do that, you could probably go a full 24 without much suffering!

Dr. Rosedale sums up the whole subject in the simple observation that our health span and our lifespan will be determined by the proportion of our fuel that comes from fat rather than from sugar, over a lifetime.

There are a couple ways to experiment with reducing protein intake. One would be to decrease your protein on a daily basis and see how you feel. Can you still exercise, think, sleep normally? An alternate plan would be to have five days a week of higher levels of protein and two (light activity days) of little to no protein. I’d be curious to hear if you experiment with Dr. Rosedale’s lower protein suggestions.


For our health and our longevity, the way we fuel our bodies is crucial and important, but we also need to maintain our activity levels and our strength.

A muscle that is naturally tending toward weakness (i.e., an aging muscle) needs to be fed (protein, as described above) and challenged to allow it to remain strong. These requirements are even more pronounced if you want your muscles to actually grow stronger.

I cannot say this strongly enough: find something enjoyable to do that offers your incredible body a chance to work really hard. Join CrossFit or find a personal trainer and make sure they know very well where you’re starting and where you’d like to go. I encourage my patients to tell the trainer to put down the little 5-lb weights used for dozens of bicep curls and show them instead how to use body weight or actual heavy weights to challenge muscles to grow even stronger. Defy that age-associated tendency to wither on the vine, and see all your musles can do for you … if you ask them!



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