Eat Like the Animals: What Nature Teaches us About the Science of Healthy Eating

"This book is written by two entomologists , people that started off studying beetles and grasshoppers and things like that and weren’t that interested in nutrition. They’ve now become world-class nutritionists. This is probably the best book written entirely by scientists that I’ve read for a while. It is a fascinating read. It traces the authors’ gradual discovery of some fundamental laws determining the way that animals eat, starting with insects, but then moving into everything from baboons to gorillas to horses. We’ve known since the 1930s that one way to make laboratory animals stay healthy longer and live longer is to allow them to eat much less. So if we take a laboratory mouse and feed it 30-40% less than it would like to eat, it will live 20-30% longer and stay healthy longer in just about every way that we can measure. What the authors have come up with is that it’s not so much the amount of food that’s important, but the composition of what’s eaten, and also the continuous availability of the food. They’ve seen it in grasshoppers, beetles and baboons. Animals, including people, will eat to get a certain amount of protein. If they’re eating a very low protein diet, they will keep eating more and more and more till they get up to that level of protein. What’s happened in modern times is that we have ultra-processed, high-fructose corn syrup foods, so it takes a lot to get up to our protein quota. That explains a lot of overeating. They got into the longevity business because somebody told them, ‘If you feed animals less, they live longer.’ They said, ‘Really? All of our research says it’s actually the protein.’ They did a bunch of experiments on fruit flies where they gave them different diets and looked at which ones lived the longest. It was the ones that had the proper level of protein, which is considerably less than if you gave the fruit fly what it wants to eat. What it wants to eat is the diet that will make it reproduce the fastest. That makes sense—that’s what evolution is all about, reproducing the most. But if you cut back the protein, it turns on all of these survival mechanisms. Get the weekly Five Books newsletter So they divide the world into what they call the ‘survival pathway’ and the ‘growth and reproduction pathway.’ What we are really programmed to try to do is eat for reproduction, involving the growth and reproduction pathway. But if we want to stay healthy longer, what we really need to do is eat for the longevity pathway. One way to do that is to eat a low-protein diet. The other way—and this is something that they didn’t really discover, but they talk about it—is that the timing of eating may be as important as the nutrients. One of the ways that this longevity pathway, which is a molecular pathway, gets turned on is by fasting. I’ve done a lot of research in this area myself, on mice. When we’re restricting the mouse’s food it will eat all its food for the day in half an hour, and so it’s fasting for 23.5 hours. Suddenly people were wondering whether it might be the 23.5-hour fast that’s the important thing and not the amount that’s eaten. That looks like it might be the case. That’s why you’ve had the development of all these intermittent fasting diets, where you only eat between noon and six o’clock or different amounts of time. It’s a fascinating development. The whole Sinclair book is a lot about genetics, but this book is all about nutrition, the way that nutrition feeds into health and longevity. They don’t make any grandiose predictions, they just say that if you want to maximize your longevity and your health, this is the proper way to think about what you eat."