Sugar Caned Tain Little Or No Fibre, for Instance

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NUTRITION — yet even Lustig identifies fresh fruit as part of the solution. The problem is surely eating too much sugar per se, and the consumption of sources such as syrups and juices that con- Sugar caned tain little or no fibre, for instance. There are few overt errors in Fat Chance — but the assertion that “burning a pound of David Katz finds much to chew on in a polemic on the fat liberates 2,500 calories” is one. The figure risk of consuming too much high-fructose corn syrup. is 4,086 calories (454 grams in a pound, and 9 calories per gram of fat). Lustig then goes on to develop a whole argument against the xcess sugar deserves to be in the spot- Lustig is correct relevance of calories and the role of exercise in light that Robert Lustig shines on it. in saying that excess weight control based on the error. However, And Fat Chance, at its best, is genu- added sugar in our the best data source we have for sustained Einely illuminating. diets is a salient liabil- weight loss, the US National Weight Control Lustig, a medical doctor and endocri- ity of modern eating. Registry, indicates that routine exercise is an nologist, has provided obesity treatment to His insights on food- almost universal feature in such success. children and adolescents for 16 years — dur- industry manipu- Fructose, writes Lustig, is Darth Vader. ing which time the condition has overtaken lations that create That presumably makes Lustig Luke nearly 20% of that age group in the United processed foods that Skywalker. There is much more to the States. In 2009, his YouTube video Sugar: The Fat Chance: are addictive, or nearly universe of our dietary concerns than this Bitter Truth went viral. Now, in Fat Chance, Beating the Odds so, are cogent and one encounter, such as unwanted chemicals Against Sugar, he lays out the case that sugar — and fructose Processed Food, compelling. His argu- in food, refined starch and trans fats. But we in particular — is the leading cause of obesity Obesity, and ments for effective pol- would surely benefit from eating less sugar, and metabolic diseases in both young people Disease icy, concerns about the and Lustig is on a mission to make it happen. and adults. He also touches on the impor- ROBERT H. LUSTIG conflicted interests of May the force be with him. ■ tance of other dietary factors, such as fibre. Hudson Street: 2012. the US Department of The book is, ostensibly, Lustig’s opportu- 336 pp. $25.95 Agriculture, and rebut- David Katz is the founding director of nity to explain in detail why fructose — pre- tals to misguided rants Yale University Prevention Research Center sent in many foods in syrup derived from against ‘nanny state’ intrusions are entertain- in Derby, Connecticut, editor-in-chief of heavily subsidized maize (corn) and other ing and enlightening. The examples — nota- the journal Childhood Obesity and sources — is the one thing really wrong with bly one in which a sweetened yogurt is shown president-elect of the American College our diets and health. But it is also an opportu- to be a dairy product acting as delivery vehicle of Lifestyle Medicine. nity to acknowledge that there is more to the for a soft drink — can be quite stunning. e-mail: [email protected] story. He manages the reconciliation of these But there are inconsistencies. Lustig two conflicting agendas with variable success. says that fructose is a particularly Some solid science underlies Fat Chance. bad actor because it does not Lustig has published dozens of articles lay- trigger an insulin release. ing out his case against sugar in general, and That lack of insulin, he fructose in particular. He participated in the says, means that levels of

DNY59/ISTOCKPHOTO.COM DNY59/ISTOCKPHOTO.COM development of an official position on the the hormone leptin — role of sugar in cardiovascular health for the which influences appe- American Heart Association. His book is at tite and fat accumulation its best when telling us why fructose is bad. — do not rise, leading to Dietary sugars trigger a release of the persistent hunger and hormone insulin, which facilitates both the overeating. But elsewhere uptake of glucose by our cells for immedi- in the book, Lustig writes ate use as fuel and the conversion of excess that the insulin resistance calories into fat, for storage. Lustig makes the caused by fructose consump- case that fructose is preferentially stored as fat, tion leads to elevated levels of and preferentially taken up by the liver, where insulin in the bloodstream, fat accumulation is most harmful. Fructose, interfering with leptin signalling, Lustig notes, shares metabolic pathways with and leading to overeating. Can a ethanol, and its consumption is linked to a lack of insulin release and excessive range of adverse conditions. One is hepatic insulin release be the same problem? insulin resistance, in which insulin recep- And what about glucose? This is a com- tors in liver cells become desensitized to the ponent of most sugars we consume, from actions of insulin, leading to a demand for sucrose (table sugar) to high-fructose corn higher levels of the hormone and the risk of syrup to the lactose in milk (which contains pancreatic stress and diabetes. Another, met- equal amounts of glucose and galactose). abolic syndrome, is a Glucose does trigger an insulin release, so NATURE.COM constellation of factors if high levels of insulin are among the per- For more on sugar associated with insulin ils of excess sugar intake, the argument that and public health, resistance, including fructose is uniquely bad is suspect. This is see: abdominal obesity and compounded by the fact that fruit is the one go.nature.com/hijnsu high blood pressure. common source of pure fructose in our diets