I’ve been advocating reducing protein intake, and particularly reducing consumption of the the branched chain amino acids (BCAA) isoleucine, leucine and valine. The goal of the protein restriction is to increase insulin sensitivity to aid in weight loss.
For years I’ve struggled with fasting blood glucose in the prediabetic range (115-120). This morning my fasting BG was 80. I had my cassava pancake breakfast (130g cassava flour topped with generous maple syrup and fruit preserves) and two hours after I began eating the pancakes my BG was at 92. This is some serious magic.
This week, results of a citizen science low-BCAA weight-loss trial organized on r/SaturatedFat by user u/springbear8 were impressive. If you haven’t seen the results you should go read them now!
How much protein does one need?
Needless to say, this approach has raised some eyebrows in the community. The concern is muscle loss.
A 1971 paper (Weller, 1971) seems to be a landmark in this field. This paper builds on the pioneering work of Dr. William Rose in determining the minimum amount of amino acids required to achieve protein balance in adult men (unfortunately no women). Amino acid balance is defined as dietary nitrogen is equal to or (slightly) greater than urinary and fecal nitrogen. The 6 men stayed in a metabolic ward for 81 days in this study. The men were young – between 21 and 31. They were lean – average BMI 20.9 – and they exercised daily during the experiment. The exercise consisted of 30 minutes of walking on a treadmill at a 10% grade at 3mph plus 15 minutes at the same grade jogging at 5 mph.
For 9 days they consumed a zero protein diet to measure baseline nitrogen excretion. Protein excretion on the zero protein diet was ~18g/day.
For the next 21 days, they consumed diets of varying amino acid levels that contained 22g of protein. The diet supplied the protein as purified amino acids in a pattern that matched that of egg whites but with supplemental glycine, glutamic acid and alanine as a source of non-essential amino acids. This number had been suggested by Rose as a minimum for humans and is slightly more than what the men excreted on a zero protein diet. Not coincidentally, my preferred source of protein is collagen/gelatin, which contains ~40% of amino acids as glycine, glutamic acid or alanine.
The diet the authors call 3.5E supplied 22g of protein per day and led to a loss of ~2.2g of protein per day. This rate of protein loss would result in a pound of muscle loss every 37 days.
The study participants then consumed a diet supplying 75g of protein for 9 days to replenish muscle tissues before consuming a series of diets of differing amino acid composition that supplied 44g of protein. (I am using the conversion factor: 1g nitrogen = 6.25g protein)
The diet called 7E+ supplied 44g of protein per day and resulted in a positive balance of ~3g of protein per day. As you go from 22g of dietary protein to 44g, most of the additional amino acids are broken down and excreted in the urine.
The table below shows the essential amino acid content of the two experimental diets. Branched chain amino acids are in italics. The third column is similar to what I’ve suggested as daily protein intake for the Emergence Diet: 3 whole eggs plus 30g of gelatin (or protein from collagen, bone broth, pork rinds, etc). The final column is protein from 6 oz of lean ham.
|3.5E (Weller, 1971)
|7E+ (Weller, 1971)
|3 Eggs plus 30g gelatin
|6 Oz Lean Ham
|Essential Amino Acids
|Total Amino Acids
So how much protein do we need?
There are a thousand variables to consider here. The most relevant ones:
- Obese humans may be in “protein sparing” mode, similar to torpid animals, and thus require less protein
- Humans that are actively losing weight will also be losing protein. This isn’t a bug, it’s a feature. When you gain fat you gain protein and vice versa. Some of this broken down protein can be recycled for needs elsewhere
- Older humans may suffer from sarcopenia: age-associated muscle loss. If you are in this category, perhaps protein restriction isn’t for you.
- If you are doing heavy anabolic exercise, protein needs may be increased
- If you are pregnant or nursing, you will have higher protein needs
- Protein digestibility may differ between protein sources and between individuals. This experiment used purified amino acids which I believe are absorbed very efficiently
Having Said That….
Young, lean, active men are NEARLY protein stable consuming a diet based on 22g of egg white protein (3.5E). In fact, 2 out of the five men whose excretion were measured on this diet WERE protein stable (subjects 3 & 4). This diet produced minimum protein excretion at 24g/day.
As protein increased to 44g per day (diet 7E+), excretion increased to 40.8g/day. This suggests that ~76% of the additional protein was unnecessary and simply excreted. On the other hand, 24% of that protein was retained, so we can say that the amino acids provided by 3.5E were insufficient to meet need.
Most convincingly, 6 out of 6 men on the 7E+ diet were in positive protein balance. This suggests that the vast majority of people would have their protein needs met by 3 eggs and 30g of gelatin daily.
It’s unfortunate that no women were tested in this experiment or others that I’ve seen from that era when basic needs were figured out. I think it is reasonable to assume that amino acid needs will roughly mirror caloric requirements.
The men consumed 2690 calories per day on average. Diet 3.5E would have provided 3.3% of calories as protein and diet 7E+ would have provided 6.6% of calories as protein.
Really?! 44g of protein?
This amount is within the historical experience of humans. Mann reported in 1955 on the diets of Nigerian tribes. The staple foods of the Ibo were low protein tropical tubers: yam and cassava. Their total protein intake was 46g of reasonably high quality – 20g of it came from animal sources. This is broadly in line with my recommendations for the Emergence Diet.
I have had astonishing results restricting protein to regain glucose tolerance and for weight loss. The recent trial posted on Reddit suggests this approach may be quite broadly applicable for weight loss.
Many are concerned about the level of protein restriction that I am suggesting. The data suggests that getting 44g of protein per day with half of it from high quality sources such as eggs or meat is sufficient to meet the needs of most adult humans. Collagen based protein – collagen, gelatin, bone broth, pork rinds, beef tendon – is an ideal source to supply the remainder of non-essential amino acid needs.
I’ve said from the beginning that I hope to be protein adequate but not more. My intent is to continue this approach until my target weight is met and then to add back more protein. Protein isn’t BAD, it can be quite thermogenic but those of us with insulin resistance are probably not breaking it down efficiently, which adds to the problem.
Mann, G. V., B. M. Nicol, and F. J. Stare. “Beta-Lipoprotein and Cholesterol Concentrations in Sera of Nigerians.” BMJ 2, no. 4946 (October 22, 1955): 1008–10. https://doi.org/10.1136/bmj.2.4946.1008.
Weller, Lee Alyce, Doris Howes Calloway, and Sheldon Margen. “Nitrogen Balance of Men Fed Amino Acid Mixtures Based on Rose’s Requirements, Egg White Protein, and Serum Free Amino Acid Patterns.” The Journal of Nutrition 101, no. 11 (1971): 1499–1507. https://doi.org/10.1093/jn/101.11.1499.