As the American Association for the Advancement of Science's annual meeting begins, we talk to the society's outgoing president and survey some hot topics
"A calorie is a calorie is a calorie" no matter what food item it comes from has long been a maxim of nutritional science, writes Stephen Phillips.
In baseball parlance, Penelope Greene's recent results dealt many dieticians a curve ball. The Harvard School of Public Health scholar found that among the 21 subjects on her 12-week study, those on low-carbohydrate "ketogenic" regimens, similar to the Atkins diet used by celebrities such as Jennifer Aniston (above, top) and Geri Halliwell (bottom), were able to consume 300 more calories a day than those on regular low-fat diets and shed more weight. The findings confounded the laws of thermodynamics, which say more calories add up to more weight.
Greene suggests the reason may be that digesting increased protein consumes more calories than digesting carbohydrates.
The findings are hotly disputed, and many sceptics worry about the health effects of reducing carbohydrate intake and consuming copious quantities of animal protein. Hence the title, Food Fights, given to the AAAS conference session Greene is hosting. Her study was funded by The Dr Robert C. Atkins Foundation, the diet franchise's research arm, and has yet to be peer reviewed and published in a scholarly journal. But Greene's primary reason for undertaking it, she says, was to establish controls for authoritative research.
Previous studies didn't monitor subjects' intake, leaving them open to suggestions that people ate less because they got bored of the menu. Greene made sure all her subjects' meals came from a posh restaurant. Instead of the red meat and saturated fat that have raised hackles about ketogenic diets, subjects were dished up fish, poultry, salads and vegetables cooked with unsaturated oil.
Nutritional research may be on the cusp of a paradigm shift, Greene says. "More people are (now) saying: 'There seems to be something to this. We need to study it further.'"
The "Food Fights" session takes place on February 16 at 8am.