Update on the Paleo diet

I promised updates on how my two-week dabble with the paleo diet. Then, in the two weeks since I started, I didn’t update at all. I’ve finished it now, so I think this may be the best time to reflect. Also, there is some science near the end, if science is more your style.

As you may recall, I had concerns about running an experiment about the effects of the paleo diet on myself. The paleo diet is very low-carbohydrate, but I always understood that your body needs to metabolise carbohydrates into glucose to fuel your brain; there simply is no other fuel source for your brain. In terms of the traditional calorie sources (carbohydrates, fats and oils) this is true. Over the first few days, when I felt tired and foggy, I considered giving up on the diet. After all, it is not worth sacrificing mental acuity for a mild investigation.

That did change, though. I now feel invigorated. I am sleeping better and think I am working more efficiently. That seems to support the theory I read before taking this challenge on: your body metabolises fats into fatty acids and ketone bodies when there is insufficient carbohydrate, and the brain can use ketone bodies for calories. I spent the first five days perpetually hungry, although that has also eased. The friend who started my involvement with the paleo diet lost his perpetual hunger after 3 days; he used to eat like he had an eating disorder. It seems it is good at down-regulating hunger. My 5 day insatiable hunger is probably due to lifting heavy things at the closest gymnasium (not that heavy).

Another benefit of this diet is that it is meant to keep certain mental issues at bay. Doctors have used it to control uncontrolled childhood epilepsy since the 1920s, and there is even evidence that a low carbohydrate is good for preventing alzheimer’s disease. So the diet is not bad. In fact, these mental factors would seem to make sense. The paleo diet is the closest diet to what we ate in our evolutionary past. It seems reasonable that our organs and brains spent a long time evolving around a diet much like the paleo diet. The brain metabolised both ketones and glucose for energy, but it uses them differently. Both these chemicals are taken up by a different pathway in the brain. The pathway glucose is metabolised through in the brain is an area of the brain related to Alzheimer’s disease. The brain metabolises ketones via another pathway. It is not a leap to suggest (although no significant body of data seems to exit, feel free to do the research yourself) the pathway the brain metabolises glucose through simply has not evolved to  deal with the traffic of glucose we give our brains.

I’m a bad study for weight loss, because I have attempted to get my fitness back at the same time. However, the person I am doing the diet with has lost eight pounds in eight days (at that speed, I can only assume it is lost water retention). The blogger ‘becoming imago’ reported losing five pounds on the diet before plateauing, and reported greater intestinal health. I can report I show signs of increased digestive health: regularity and lesser compliance to gas laws. I weighed 12 stone and 1 pound before I started on 4th January. On 13th January, according to the same scales, I weighed in at 11 stone 5. For those who don’t know stones, I’ve lost 10 lbs (4.5kg) in 8 days. Not bad. My weight has now plateaued. But I look leaner.

The reason for the weight loss is also speculative, but I have two reasonable ideas. The first is insulin rebound. Our metabolism is tuned to respond to the sugar in our bodies. In evolutionary time, if sugar appears in our digestive system that sugar level is going to go up slowly for a while as our body digests complex carbohydrates. Our insulin level trails behind, storing excess. In today’s diet, it is possible for sugar levels to spike. Our body has evolved to react to this as if sugar levels are going to continue to go up at this speed. We get huge surpluses of insulin and that stores too much sugar, which prohibits our bodies from using it. That’s a sugar crash. It becomes very difficult to burn off the sugars because insulin levels are high. Then, because we have low blood sugar (because excess insulin has stored it all) we get hungry. Sugar is bad at regulating hunger.

My second theory is that it’s just a lot harder to get calories in. I cite both the low-calorie density of the food I did eat and my lack of sustained physical energy at the gym. Although I had a lot of energy for all other things, the level of intensity I could sustain was lower than I am used to.

Summary: increased mental acuity and digest health; decreased weight, but also energy levels (for sustained exercise). Evidence suggests mental health benefits.