Fed Up: A Hungry Person’s Guide to the Story and Science of Food and Diets Author: Daniel LiebermanISBN-13: 978-0241658598Publisher: Allen LaneGuideline Price: £25; 416ppDiets, in the long term, rarely work. This isn’t because human beings are cursed with zero willpower. No, there are factors at play here that are biological, evolutionary and almost impossible to resist.There’s another important truth that Daniel Lieberman, a professor of biological sciences at Harvard University, returns to throughout his book Fed Up: weight is not a cast-iron indicator of a person’s health. Yet diets are commonly prescribed to people perceived to have a “weight problem”; the stigma and misinformation around fat remain painfully slow to overthrow. Fed Up follows Lieberman and, occasionally, his wife Tonya, as they subject themselves to several fad diets that claim to have solved the riddle of the human body. These two-week experiments aren’t in themselves the most revealing aspect of the book – talking to people with more substantial first-hand experience of the woes of dieting may have been more insightful – but they do give the book a narrative thrust as Lieberman presents complicated science in a way that’s accessible.Okay, the jokes don’t always land, but this attempt at levity does produce some fun passages. I particularly enjoyed Lieberman’s description of fugu, a potentially deadly seafood dish, as having “a pleasant, silky, firm texture but disappointingly subtle taste overpowered by the remote risk of a horrible death”.The fulcrum of Lieberman’s analysis is the very simple formula that drove early man: “food in, babies out”. From there, he draws on his extensive background in evolutionary biology to explain why our dietary habits evolved into what they are today, and what different foods do for and to our bodies.Of course, human anatomy is a complex machine. From a dieting standpoint, Lieberman smartly summarises this by pointing out that losing weight is not simply the opposite of gaining weight. “There is no simple way to outsmart these ancient adaptations,” he writes.The science can sometimes be dizzying; readers may find their brains skidding over the textbook-style diagrams. But Lieberman’s attempts to make it all comprehensible are mostly a success. If nothing else, Fed Up will inspire readers to put their own fridge under deeper scrutiny.