One of the most-cited vegan athlete success stories is of Carl Lewis, who credits his outstanding 1991 results in part to the vegan diet he adopted in 1990.(1) He says something that is often quoted in vegan propaganda,

“My best year of track competition was the first year I ate a vegan diet.”

The biohacker in me read that and said, “but what about the year after that?” The results are predictable, at least if you’ve read a previous post about measuring power in vegetarian athletes. It’s also a little known fact that a high omega-6 diet masks cellular energy deficiencies for a short period of time (more on that below).

The Facts About Going Vegan That Are Left Out

Here are the facts. Before going vegan, Lewis consistently dominated both sprinting and the long jump. After the heights reached in 1991, only 1 year after starting the vegan diet, Lewis started to lose his dominance in both the sprints and the long jump.

In 1992, he failed to qualify for the Olympic team in the 100 m or 200 m. Lewis did, however, qualify for the long jump and was eligible for the 4 x 100 m relay team. The vegan diet was starting to take its toll. Then in the 1992 Olympics, he ran a very fast 4 x 100 relay and won the long jump, but with a shorter jump than in previous years. He was unable to compete in his formerly strongest events – the 100m and 200 m sprints.

Then in 1993, Lewis competed at the 4th World Championships in Stuttgart, but finished fourth in the 100 m sprint and did not even compete in the long jump. He did win a bronze medal in the 200 m sprint, which was his final Olympic or World Championship medal in a running event.

Starting in 1994, injuries kept Lewis largely sidelined for the next few years.

An impartial observer would say, “Here is a world class athlete who was performing very well across the board. Then he went vegan, had one great year, got progressively less consistent, and was ultimately sidelined by injuries.”

The Vegan Trap

Here’s the reason I believe this happened, courtesy of Steve Fowkes (click here to listen to the Bulletproof Radio episode with Steve Fowkes), a friend and one of the wisest biochemists I’ve ever known, and author of Smart Drugs & Nutrients II, one of the “bibles” of cognitive enhancement. Steve writes: (bolding is mine)

Unfortunately, the benefits to consuming a PUFA-containing product do not counteract the rancid-oil exposure. Furthermore, the non-rancid PUFAs deposit in the fatty tissues and cell membranes of the body where they become targets for oxygen free radicals. This is the bad side. The good side is that the PUFAs promote membrane fluidity and membrane permeability, which has a pro-metabolic effect that is in some ways similar to that generated by thyroid hormone, progesterone, exercise, vitamin D, vitamin A (not beta-carotene), magnesium and selenium (and other agents). But because it mimics the effects of these other agents, there can be perceived benefits that are not truly biologically sustainable. In other words, there is a perceived health change for the better, but I believe a vegan diet contributed to his rapid decline.