Those of you who follow my posts know that I’m a big believer in self-restraint. In the last 15 years, I’ve had no alcohol, no caffeine, no meat, no pills, and no fast food. Health-wise it brought good results: I only had a fever once in the last 15 years. Typically, I just don’t get ill.

A year ago I added more restrictions to my diet: no gluten, no dairy, no eggs, no fructose. I did it to achieve higher productivity and clarity of thought, as well as to train will power and self-discipline.

Another technique I employ to improve will power is swimming in ice-cold water every winter in Finland or Switzerland. If you ever faced the necessity to stay in a lake with a thin layer of ice on top for a few minutes, you are less likely to procrastinate when it comes to starting on a boring but necessary project.

In May I limited the foods I eat to fish and seafood only. In case you have daily access to fresh wild-caught fish, I can definitely recommend this diet for boosting productivity. Unlike farmed meat or the…