Dr Katz, director of Yale University’s Prevention Research Centre, says people stop eating when the brain’s appetite centre registers “full”. But eating lots of flavours promotes overeating because different sensors must register full for appetite to subside, he says.
The typical American diet “is a mad cacophony of flavours”, Dr Katz said this week.
Instead, he advocates flavour-themed meals - an apple day, for example, or a sesame day, even an occasional chocolate day.
The idea is perhaps less boring than it sounds. For example, pineapple day features pineapple juice and cereal for breakfast; pineapple-walnut chicken salad and crackers for lunch; pineapple shrimp, bulgur, sauteed peas and tossed salad for dinner; and caramelised pineapple rings for dessert.
The theory and practice are detailed in Dr Katz’s new book, The Flavor Point Diet, based on a little-publicised phenomenon called sensory-specific satiety. That is the term used to describe the way food becomes less palatable when enough of it is eaten. Adding a new flavour renews the process, numerous studies have shown.
Dr Katz tested the diet on 20 people for 12 weeks and said they lost an average of over 16 pounds.
Jonathan Link, a 34-year-old who was 5ft 9in and 183lbs, with high cholesterol, was one of them and was sceptical at first.
But he said the diet was surprisingly varied. He lost about 20lbs early last year and has kept it off by permanently changing his eating habits.
“By week two, I started getting stuffed. I couldn’t even finish dinner because I was feeling so full,” he said.
Dr Katz recommends 30 minutes of moderate exercise most days. His flavour theme builds on the diets many nutritionists advocate - lots of fruits and vegetables, whole grains and nuts; fish and poultry for protein; limited fat; and healthy snacks.
Brown University researcher Hollie Raynor, who has studied sensory- specific satiety, said many diets are based on a more extreme interpretation of the concept, including ice cream diets, soup diets and diets that severely restrict carbohydrates.
Whether Dr Katz’s diet works because it limits flavours, or because it promotes healthy eating and exercise, is unclear, she said.