I work as a professor in the University of California, San Francisco School of Medicine and at the UCSF Clinical and Translational Science Institute. This allows me to connect with other scientists who come from very different backgrounds but who want to work together on big problems -- think of a Manhattan Project, only one focused on protecting health through the collaboration of scientists who study everything from tiny cells to entire societies.
So three years ago, a pediatric endocrinologist named Rob Lustig walks into my office and asks for my help. Rob tells me that he's finding many connections between the metabolism of fructose (sugar) and ethanol (alcohol) in his work on metabolic functioning, liver damage and the obesity epidemic.
Rob runs the obesity clinic at UCSF Benioff Children's Hospital, where he spends his days trying to help morbidly obese kids who feel hungry all the time. One of the saddest effects of sugar overconsumption is to dampen the natural hormones that tell kids' bodies when they've eaten enough, leading them to feel hungry even as they overeat.
Rob says he's also seeing that too much sugar in these kids' diets causes severe liver damage -- they have even started doing liver transplants on some of the kids in his clinic.
Fast-forward to today, and here's what we've learned:
-- More people on the planet Earth are dying from chronic diseases such as heart disease, stroke, cancer and diabetes than anything else. This is even true for developing countries that have turned a critical page on health: People in those countries are now more likely to die from the "diseases of affluence" than from the "diseases of poverty" like malaria and cholera. Major risk factors in chronic disease, of course, are alcohol, tobacco and junk food consumption.
-- Many of the health hazards of drinking too much alcohol, such as high blood pressure and fatty liver, are the same as those for eating too much sugar. When you think about it, this actually makes a lot of sense. Alcohol, after all, is simply the distillation of sugar. Where does vodka come from? Sugar.
-- We may be thinking about obesity and chronic disease in the wrong way. Most experts are worried about sugar because it's "empty calories" that make people fat. But what leads to chronic disease is actually something called metabolic syndrome, which can be caused by the toxic effects of sugar.
-- Added sugar at the levels consumed by many Americans changes our metabolism -- it raises blood pressure, critically alters the signaling of hormones that turn hunger on and off, and can damage the pancreas and liver. Worldwide consumption of sugar has tripled over the past 50 years, and along with that has come an obesity pandemic. But obesity may just be a marker for the damage caused by the toxic effects of too much sugar. This would help explain why up to 40% of people with the metabolic syndrome -- what leads to diabetes, heart disease and cancer -- are not clinically obese.
What should we do about all this?
First, we think that the public needs to be better informed about the science of how sugar impacts our health.