The results could contribute to a deeper understanding of how people develop food and taste preferences and cravings. This may have important implications for the food industry, not just for food formulators and flavor scientists, but also with the growing epidemic of obesity..
With many critics keen to take the blame off a consumer's personal responsibility and heap it purely at the feet of the food industry this research highlights just how multi-faceted and complicated the obesity issue may actually be.
Over 300m adults are obese worldwide, according to latest statistics from the WHO and the International Obesity Task Force. About one-quarter of the US adult population is said to be obese, with rates in Western Europe on the rise although not yet at similar levels.
Roberts and colleagues observed that successful weight loss was related not only to how often people gave in to their cravings, but also to the types of foods they craved. “Participants with a higher percentage of weight loss actually craved foods with higher energy (calorie) density, compared with those who lost a lower percentage of body weight,” says Roberts, who is also a professor at the Friedman School of Nutrition Science and Policy at Tufts University. “Energy-dense foods, such as chocolate and some salty snacks, are those that pack the most calories per unit of volume,” explains Cheryl Gilhooly, PhD, MPH, research dietitian and first author of the study, “as compared to less energy-dense foods like fruits and vegetables, which have fewer calories per unit of volume.”
“These findings suggest,” says corresponding author Susan Roberts, PhD, director of the USDA HNRCA’s Energy Metabolism Laboratory. Roberts, “that cravings are for calories, not carbohydrate, as is widely assumed. What is commonly called carbohydrate addiction should probably be relabeled as calorie addiction,” she added. Some of the most commonly craved foods among study participants were foods that have high sugar plus fat, such as chocolate, and salty snacks, such as chips and French fries. “The craved foods do have carbohydrate, but they also have fat, and some protein, too. The most identifiable thing about the foods people crave is that they are highly dense in calories,” Roberts deduces.
The study, which was part of the one-year CALERIE trial, involved 32 overweight but otherwise healthy women, 20 to 42 years of age, who were randomly assigned to two diets that differed in glycemic load, a measurement of how quickly the carbohydrates in a person’s diet are converted to blood sugar.
"The craved foods do have carbohydrate, but they also have fat, and some protein, too. The most identifiable thing about the foods people crave is that they are highly dense in calories," she added.
Primary results from the CALERIE study were reported in an earlier issue of Friedman Nutrition Notes, available at http://nutrition.tufts.edu/news/notes/2007-03.html.
The study, published in the International Journal of Obesity, states that food cravings are normal, with 91 per cent of study participants reporting having food cravings. Dieting also seemed to increase cravings.
"In fact, 94 per cent of the study participants reported cravings after six months of dieting," said Roberts. "However, participants who lost a greater percentage of body weight gave in to their cravings less frequently. Allowing yourself to have the foods you crave, but doing so less frequently may be one of the most important keys to successful weight control."
The study, which was part of the one-year Comprehensive Assessment of the Long-term Effects of Restricting Intake of Energy (CALERIE) trial, involved 32 overweight but otherwise healthy women, 20 to 42 years of age, who were randomly assigned to two diets that differed in glycemic load.
Participants completed food craving questionnaires assessing the type of foods craved, the frequency and strength of cravings, and how often cravings led to eating the desired food.
"This is the first study of long-term changes in food cravings in a calorie-restriction program," said Roberts and they conclude that cravings for energy-dense foods are common. Although they caution that additional long-term studies are needed to confirm their findings, they write that their results “…suggest that people attempting to lose weight and maintain weight loss may benefit from advice to accept that food cravings may not decrease in frequency.” Controlling the frequency of giving in to cravings, rather than suppressing them, they say, may be an important area of emphasis in future weight control programs.
International Journal of Obesity- Published on-line ahead of print, doi: 10.1038/sj.ijo.0803672
"Food cravings and energy regulation: the characteristics of craved foods and their relationship with eating behaviors and weight change during 6 months of dietary energy restriction." Authors: C.H. Gilhooly, S.K. Das, J.K. Golden, M.A. McCrory, G.E. Dallal, E. Saltzman, F.M. Kramer, S.B. Roberts