As Professor Daniel Lieberman explains, once you\u2019ve written a book about exercise, the logical next step is to write one about diet<\/a>. Although, that\u2019s down playing what his book Exercised<\/em> did for the science of physical activity. His book argues that we didn\u2019t evolve to go to globo gyms to lift and run, and similarly in Fed Up: What Evolution Reveals About Food, Diet And Eating Well<\/a><\/em>, one of Professor Lieberman\u2019s central arguments is that we didn\u2019t evolve to cut calories, which is why doing it can be so unpleasant. Speaking to Men\u2019s Health<\/em>, he explains some of the influence evolution has on how we eat today, and why, contrary to popular belief, losing weight isn\u2019t as simple as calories in, calories out.<\/p>\n Daniel Lieberman:<\/strong> I taught a course at Harvard on diet called Diet and Exercise. In that class, we\u2019d pick a topic like hypertension, and we\u2019d read original papers published in respected journals where one would be saying too much salt will kill you, and the other would be saying salt arguments have been exaggerated. It was so much fun to read that stuff, but it reinforced how confusing nutrition literature is. Everybody\u2019s confused about it, so I wanted to write an anti-bullshit book about diet.<\/p>\n DL:<\/strong> There are so many people out there shilling some optimal diet or another. Most of them have a germ of truth, but there is no such thing as an optimal diet. We evolved to eat everything, and we didn\u2019t evolve to eat that stuff for the sake of living to be 100. We evolved to eat in order to have as many babies as possible. I think we lose track of the fact that, for people in places like the UK and America, we think it\u2019s normal to go into a supermarket or a restaurant and try to decide what you want to eat, but that\u2019s not normal at all. It\u2019s a completely modern, strange and bizarre thing that we\u2019re now confronted with.<\/p>\n DL: <\/strong>Most diets work if you follow them. The problem is, people have a hard time following them. They\u2019re hard to sustain and they\u2019re unpleasant. One of the arguments of the book is that we never evolved to diet. Dieting inevitably involves something called negative energy balance \u2013 ingesting fewer calories than you use. When you do that, you get hungry, and hunger is hard to overcome. There are many ways to do that, you can go for a low-calorie diet, you can go for a low-carb diet, you can go for a low-fat diet, and if you look at the data, most people in all of those major diets can lose weight, but they struggle and many people give up.<\/p>\n <\/p>\n \u2018We\u2019re stressed, hungry and tired and we want something convenient\u2019<\/p><\/blockquote>\n <\/p><\/blockquote>\n<\/div>\n The other problem is that after the diet\u2019s over, people\u2019s hypothalamus has what\u2019s called a settling point. It causes you to try to get hungry until you get back to your original weight. So there are all these adaptations any dieter has to overcome \u2013 deep-seated ancient adaptations. Then we make people feel bad because they struggled to diet or they gained the weight back, and somehow it\u2019s their fault, they didn\u2019t have willpower, but it\u2019s not their fault.<\/p>\n DL: <\/strong>That\u2019s so obviously wrong. We have these things called hormones. Ultimately, calories are very important, but your body doesn\u2019t use the calories from different kinds of food in the same way. Low-carb diets make a lot of sense, because when you eat food, the main hormone that causes you to store that food in your fat cells is insulin, and that is primarily, but not exclusively, raised by glucose, which is this sugar, so diets that keep your insulin levels low tend to be slightly more effective than other forms of dieting. There\u2019s a lot of data to support that; so, keto diets<\/a>, high-protein diets, low-carb diets \u2013 there\u2019s a variety of them. They tend to work better. The problem is that a lot of people have a hard time sustaining them, because people like carbohydrates. And it\u2019s a bit more complicated than that, too. Exercise affects how much insulin you produce from eating, so two people can eat the same amount of glucose, and one of them will produce more insulin than the other, because they\u2019re exercising. We\u2019re endlessly and constantly trying to oversimplify a very complex system. It would be nice if it were simple, but I\u2019m afraid that\u2019s not how biology works.<\/p>\n DL:<\/strong> I don\u2019t have a lot of willpower. If you put a piece of chocolate cake in front of me and a carrot, there\u2019s no way I\u2019m going to eat the carrot. Willpower is really hard to overcome, because we evolved \u2013 of course, there was no chocolate cake in the Palaeolithic period \u2013 to eat foods that are loaded with those kinds of nutrients. Do you know the only non-artificially produced food in the world that\u2019s both sweet and fat? It\u2019s mother\u2019s milk. When we were born, it\u2019s the only natural food that\u2019s loaded with salt, sugar and fat. Food producers have figured out how to make those foods, and we can\u2019t resist them. It\u2019s like a moth to a flame.<\/p>\n DL:<\/strong> There\u2019s a wonderful book called Salt Sugar Fat: How The Food Giants Hooked Us<\/a><\/em> by Michael Moss, who\u2019s an investigative journalist for The New York Times<\/em>. He went to these companies, and they have this thing called the Bliss Point. They figured out the exact proportion of sugar, salt and fat that lights up your brain and makes you want to eat more and more. They also test these foods on thousands of people. Do you know why M&M\u2019s are different colours? Because your brain gets excited by the variety, you think, \u2018Oh, I\u2019m going to try a red one, I\u2019m going to try a blue one, I\u2019m going to try a green one.\u2019<\/p>\n DL:<\/strong> It\u2019s hard. The average American supermarket has 40,000 kinds of food and about 70% of those are processed in factories and designed to appeal to these kinds of tastes. One of the arguments of my book is that we evolved to know how to get our food. Hunter-gatherers, which we were for most of our evolutionary history, had to know an enormous amount about how to find their food. And then, farmers had to know an enormous amount about how to grow their food and process it. Now, we don\u2019t have to know anything about it. You can press a button and, bam, you have pizza delivered. Now we need to learn how to choose our food.<\/p>\n DL: <\/strong>One of my favourite phrases people quote all the time is Michael Pollan\u2019s famous suggestion, \u2018Eat food. Not too much. Mostly plants.\u2019 It\u2019s a little bit over simplistic, but there\u2019s a lot behind those seven words. Most people probably know in their gut what\u2019s healthy. You go to the supermarket, and you see all these fresh fruit and vegetables \u2013 who doesn\u2019t know that\u2019s healthy? Except for a small group of carnivore dieters<\/a> who are a little bit \u2013 or a lot \u2013 on the loony side. If you see food that has all these ingredients and you have no idea what those ingredients are and you have no idea how to pronounce them, chances are that\u2019s probably not very good for you. But we\u2019re stressed, hungry and tired and we want something convenient, fast and inexpensive \u2013 and it\u2019s very hard to overcome that.<\/p>\nMen’s Health<\/em>: Why did you write <\/strong>Fed Up<\/em>?<\/em><\/strong><\/h2>\n
MH:<\/em> Do you feel you\u2019ve accomplished that, the anti-bullshit diet book?<\/strong><\/h2>\n
MH<\/em>: Do diets work for weight loss?<\/strong><\/h2>\n
MH<\/em>: So losing weight isn\u2019t as simple as calories in, calories out?<\/strong><\/strong><\/h2>\n
MH<\/em>: So whether a diet works or not isn\u2019t down to willpower?<\/strong><\/h2>\n
MH<\/em>: There is a lot of shaming around weight, which your book really rallies against. Talk to me about the link between weight and shame.<\/strong><\/h2>\n
MH<\/em>: How do people fight back against that?<\/strong><\/h2>\n
MH<\/em>: How should we go about that?<\/strong><\/h2>\n
![\"Fed](\"https:\/\/hips.hearstapps.com\/vader-prod.s3.amazonaws.com\/1790677454-41BLYZbwuQL._SL500_.jpg?crop=1xw:1xh;center,top&resize=980:*\" "\\"Fed")
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