Research has already shown that your personality can play havoc on your waistline. Now, science suggests the way you think could be key to whether you are a yo-yo dieter or a “weight-loss maintainer”. A study led by researchers at the Universities of Amsterdam and Birmingham and presented at this year’s European Congress on Obesity (May 23-26) in Vienna, Austria, has found significant differences in the physiological and behavioral responses of people they classify as "weight-loss maintainers" and those who have a much harder time keeping the weight off. First, the team monitored the heart rates and saliva responses of volunteers when they were presented with highly palatable food – think pizza and chocolate. These foods trigger a strong pleasurable response in the brain and can set off addictive-like eating tendencies. Of the 65 volunteers, 25 were currently obese, 20 were formerly obese, and a further 20 had never been obese. Participants in the former category showed an increased heart rate and a higher saliva response when presented with pizza, revealing an involuntary response to food that may make it harder to stave off the cravings. In contrast, weight-loss maintainers (i.e. the formerly obese) showed the opposite reaction – a reduced physiological response to the pizza. The 20 who had never been overweight showed a completely neutral response to the food. Next, the researchers tested the volunteers' behavioral responses to food with a computer game. They were presented with symbols, each linked to a different outcome – to win food, to lose food, to win money, and to lose money. After some time to practice and get the gist of the game, the researchers tracked which symbols the volunteers actively sought out. Of particular interest, they noted, was that weight-loss maintainers appeared to learn best from food losses (in comparison to food wins). This, they suggest, shows they could be less motivated by food and, therefore, find it easier to maintain their new weight. The study was small and observational and, as the researchers point out, a more in-depth, longitudinal study is needed to confirm their conclusion: that weight-loss maintainers place less value on food rewards and display different physiological and behavioral responses to food compared to people who put weight back on. For now, whether these physiological and behavioral responses cause or are caused by obesity is uncertain. Source
