Low Isoleucine Diet?

I do not any longer but until 6 mos ago I ate big protein at every meal plus shake before bed

Brkfst - zero fat Greek yogurt 16oz (43g protein) or shake w/40g whey protein
Lunch — protein shake (40g protein)
Dinner — fish plus (80g protein plus small protein in veg)
Prebed shake — 30g protein

Approx 200g

I kept the calories down by using very low fat sources. I continue to live on ~2000 kcal plus estimated calories burned in exercise.


There were some human trials in some of the experiments listed in that article and had similar results. It does look like limiting isoleucine had the biggest impact. Most of the experiments showed that they lost fat (and I don’t think they lost muscle). The did not restrict calories. There was even some experiments on the mice where they compared a group they had do resistance training (pulling weighted carts). Most of the experiments were to see if they could lose fat without doing calorie restriction.

That being said, if one was doing a lot of lifting or other more extreme exercise, I would be careful with the protein restriction.

I also have the question; what foods and particularly recipes that are low in isoleucine and maybe lower overall protein and not infinite carbs I.e. maybe high fat, high carbs low protein)?


Cream cakes and doughnuts would fit that description…

Fats+carbs that’s about the most fattening and unnatural combo of macros


Since I cannot isolate isoleucine, I’ll just continue to emphasize cycling anabolism around rapa. My protein by Rapa dose day:

0 — low calories and no animal protein (easy endurance exercise)
+1 — low protein (easy lifting after 30 hours)
+2 — moderate protein (moderate endurance)
+3 — high protein post workout (hard lift PM)
+4 — high protein in AM (endurance)
+5 — high protein post workout (hard lift PM)
+6 — high protein in AM (endurance)

Let me know if anyone figures out how to eliminate isoleucine without eliminating leucine.



This is not lost elasticity. This is just the visual effect of having low body fat. If you have very low body fat your face will look older even though it’s more healthy. A clear example of this is that when people that have very low body fat gain significant weight, their face immediately looks several years younger, demonstrating that it was just the low body fat making it look old, it wasn’t old.

I say that’s mostly not true, except perhaps in those that are fairly old. Resistance training plus a calorie slurpus will make pretty much anyone gain some muscles. Increased protein intake helps but is kind of unnecessary except for in older people and those that want to absolutely maximize muscle mass gains.

Anecdotally, I used to eat a lot of protein, then in my mid thirties I cut my protein intake roughly in half, and saw no difference in my ability to gain muscle mass. As long as I lift heavy weights, I will gain muscle mass if I increase my calorie intake and lose muscle mass if I reduce it, even if my protein intake remains constant. Perhaps protein intake will have more of a significant influence when I get older but for now it’s 90% the calorie intake that matters.

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Interesting. “Adequate” protein was the claim…that’s a safe bet. The question is what is “adequate”? You are saying a lot of protein is not necessary (I.e., 1 gram per pound of body weight per day). I am coming around to that perspective. Im down from 200g / day to 120-140g on anabolic days and a small amount around rapa dosing.

The body can’t make the essential amino acids but it can recycle them. I wonder what drives a need for more EAA? Anabolic resistance is a curious thing. I’ve heard it’s really a lack of stimulus. What do you think?

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Yes, it depends on what we mean by adequate. I can’t remember the exact numbers, but if I recall, studies showed that protein synthesis was maximized at a number that wasn’t very high. Maybe even a little under 1 g/lb body weight. That’s not to say that there won’t be any benefits in muscle gains from going higher than that (muscle gain is not all about protein synthesis), but chances are that higher intakes will have very small or insignificant additional benefits. Note that the body mostly adjusts to higher protein intakes by increasing protein catabolism and adjusts to lower intakes by reducing protein catabolism to reach a relatively neutral nitrogen balance regardless of intake.

FYI in my thirties I reduced my intake from something around 1.2 g/lb body weight to closer to 0.6 g/lb body weight and noticed no difference in ability to gain or maintain muscle mass. That’s just an n=1 of course. Maybe some other people notice a difference.


1.63g/kg iirc (see Brad Stanfield)

I pull people’s faces/cheeks day in day out. I know what they feel like. That is not just a lean face but one of that has lost all elasticity

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Basically around 0,7 g/lb. @Olafurpall your 0,6 g/lb is almost there. I believe around 90-110 g per day of protein is adequate, everything more wont make big difference. This is in line with BJ macros. But in building and having muscly body there is also a vanity aspect. Great strength, mobility and muscle mass are not really necessarily correlated.

I guess it depends on which guru you choose to listen to.
I certainly hope the amount required when you are old isn’t as high as some claim, because it is hard for me to get over 100 grams daily. I am never hungry and I
can only stand to eat so many eggs, steak, etc to get the amount I would like to have.


A related conversation… A Life-Extension Drug for Big Dogs Is Getting Closer to Reality (Wired)


That muscle protein target is about optimizing muscle gain in a specific period. It does not say anything about longer periods, where muscle gain might still happen with lower protein but not as fast.


I’m surprised this paper isn’t being discussed more. Just published in Cell Metabolism but I linked the open-access preprint.

we found that consumption of a Low Ile diet from 6 months of age significantly increased lifespan, with a 33% increase in median lifespan relative to Control-fed mice (Fig. 6S ). Somewhat surprisingly, despite inhibiting frailty, a Low AA diet had no effect on median lifespan (Fig. 6S ). A Low Ile diet also increased median lifespan in females relative to Control-fed mice by a more modest 7%; once again, there was no effect of a Low AA diet on median lifespan (Fig. 6T ). We also observed a significant effect of diet on maximum lifespan (90%); in males a Low Ile diet increased maximum lifespan relative to both Low AA-fed (by 13%) and Control-fed (by 17%) fed mice (Fig. 6U ). In females, a Low AA diet significantly increase maximum lifespan relative to Control-fed mice by 12% (Fig. 6V ).

These effects are really remarkable, especially for the guys. This is a much more conservative approach than protein restriction, and yet the results are far superior.

My plan to incorporate this is to initially start by using collagen to meet 36% of my protein demands. This should reduce my isoleucine intake by somewhere in the neighborhood of 30%. Another possibility is exclusively using collagen for bulk protein intake, and then supplementing the other indispensable amino acids. This would place me around the needed 67% reduction in isoleucine intake. My primary concerns with this second approach are adherence and the cost and purity of the remaining amino acids.


A little math…

In the original article linked by Joseph_Lavelle if you look at Table S1 in the supplemental information, a two-thirds reduction in isoleucine means a diet of 2.54 grams of isoleucine per kilogram (3900 kilocalories) of food.

I don’t know if mice require nutrients in different proportions, but if human metabolism is similar, then we can extrapolate: If your diet is 2000 kilocalories, then limit isoleucine to 1.3 grams per day, which according to MyFoodData linked by JuanDaw is about the amount in 3 ounces of lean braised cube steak or 6 ounces of roasted turkey breast. If your caloric intake is higher or lower, then adjust proportionally, and you can use the same website to look up equivalent levels in plant-based sources.


Thanks, but how to do that AND still get enough leucine for MPS. Maybe it’s enough to have low isoleucine on my low protein days?

You could try nutritional yeast. It has 37 mg of isoleucine and 64 mg of leucine per gram.

Two tablespoons will give you 120 calories, and 18 grams of protein.

That is the equivalent protein content of the meat with lowest isoleucine content (dry pork and beef sausage). It would have 980 mg isoleucine,

and 378 calories.


@JuanDaw thanks for the data. Nutritional yeast is a good idea. And it tastes so bad that I’ll get a placebo effect as well. I’ll never forget the first time I tried it at the beginning of my health improvement efforts 15 years ago…I took a big gulp, and barely kept it down. But my palette has “evolved”. Thanks again.


Just had it now over bread and olive oil. Taste to me is umami. I also use it to flavor soups and stews.

You may be referring to brewer’s yeast with the bad taste.