The Protein Leverage Hypothesis

I read the cracking 5 Appetites book last year.

It’s disappointing, though not remotely surprising, that interesting new ideas about nutrition have to come from unorthodox sources; in this case two entomologists (that’s insect folks) David Raubenheimer and Stephen Simpson. They have made interesting discoveries about how appetite works in various species, finding similar mechanisms, first in insects and subsequently in mammals, and in some small studies on humans. Their endeavours are covered more painstakingly that you might wish in their otherwise excellent book that I highly recommend.

The Big Ideas

The key takeaways.

• We have more than one appetite
  • We don’t have a single appetite.
  • Rather, we have multiple appetites for a range micronutrients and macronutrients, reflecting our body’s various needs.
• Multiple tastes evolved for this reason
  • Our basic tastes are sweet, sour, salty bitter, umami, maybe fat.
  • This number is a compromise, but were sufficient in our ancestral environment to guide our behaviours to seek out and consume the multitude of nutrients we needed to prosper.
• Protein is our overriding appetite
  • Broadly, we eat to protein satiety.
  • In a protein-poor, energy-rich environment, we’ll overeat calories to get the protein we need.
  • In a protein-rich environment, we’ll under-eat calories, stopping when our protein needs are met.
  • This has been shown to be the case for locusts, pigs, rodents, fish, non-human primates and, tentatively, us humans.
• Alas, whilst some protein is good, more isn’t necessarily better
  • An obvious corollary from the above is that if we want to lose weight, we should simply increase the proportion of protein in our diets relative to carbs and fat.
  • And, actually, it will probably work.
  • But there’s a catch - as they say, there’s no such thing as a free, protein-leverage lunch.
  • Protein consumption stimulates “growth” pathways that hasten aging and shorten lifespan in the animals studied.

A part-explanation for the “obesity crisis”?

Protein is an expensive ingredient compared to carbs and fats - especially those that are used in processed foods - and so has declined relative to the other macronutrients in our food supply. It’s not at all impossible that this has contributed to the epidemic of weight gain, obesity and related diseases as we eat enough food to get the protein our bodies need, whilst exceeding our energy requirements.

Growth and Longevity Pathway Broscience 101

So, what are the cool kids doing, you ask? I have no idea, of course, but here’s my take.

Protein is important for growth and general well-being - this Peter Attia podcast with Don Layman makes a compelling case. It’s probably more important as we get older as our ability to synthesise and re-synthesise protein degrades as we age. Plus, of course, it’s essential to load up on protein if one is trying to maximise one’s gainzzz from shifting iron around in the gym.

My solution; for six days a week I eat around 2g of protein per kg of bodyweight, and one day a week I go completely without food. The latter, fun, intervention is intended to stimulate the “longevity” pathways to help offset the time spent with the “growth” pathways activated. Neat, plausible - probably wrong.

Anyway, not to worry. I’ll let you know how it pans out twenty or thirty years from now.