Many dieters’ experience difficulty adhering to diet plans when faced with the temptation to eat tempting energy dense foods. However, healthy foods that are associated with diets, such as salads and fruits may remind dieters of their long term goals to lose weight and improve self-control. Researchers at the University of Leeds asked women to smell either fresh oranges or chocolate and to write about memories triggered by the smell of the foods. After smelling the foods participants could help themselves to chocolate, cereal bars and oranges. The researchers found that women who were dieting to lose weight ate 60% less of the chocolate after smelling fresh oranges compared to smelling chocolate. In contrast non-dieters ate similar amounts regardless of the food they were exposed to before snacking.
In a second study, food or non-food images (e.g. office equipment) briefly appeared on screen while participants completed an on-going distractor task on the computer. When provided with the opportunity to eat a variety of sweet and salty snack foods dieters who were shown healthy food images ate less than dieters who were exposed to non-food items.
As well as the sight and smell of healthy food, actually eating healthy food can help dieters cut back on the number of calories consumed in an evening meal since the healthy food serves to remind the dieter of their diet goal and promotes feelings of fullness for longer. In a third study the researchers gave participants either a salad, garlic bread or water and then offered pizza as a main meal. They found that despite the salad and garlic bread being the same amount of calories, female dieters ate less over the two courses if they consumed the salad appetiser compared to an appetiser of garlic bread or water. While non-dieters ate similar amounts when salad was the appetiser compared to the garlic bread and water.
The effects of healthy food to improve dieters’ self-control may be most beneficial to dieters when they are hungry. For example, in a study where dieters were given a standard lunch then offered a snack 2 hours later, there was no effect of diet-congruent odours (fresh orange) on intake. Thus, diet cues might be most useful to dieters when they are hungry and tempted to overindulge in snack foods.
The findings have implications for diet strategies. Doctoral research student Nicola Buckland suggests that “when tempted by food, dieters should take a few moments to focus on the sensory properties of healthy food, such as the sight and smell of fruit or salad vegetables. Such healthy food cues can provide an instant reminder to dieters to regulate their intake”. Buckland suggests that “increasing the presence of healthy foods in places where overeating is most likely to happen, such as the fridge, kitchen cupboards and on the desk at work, may help remind dieters to limit their food intake.” Even when away from home dieters can prompt resistance to temptation with a piece of fruit or baby carrots “when eating out order a salad as a starter to help reduce intake.”
The research was funded by The Coca-Cola Company.
Lead Author: Buckland, N.J., University of Leeds, UK.
Co-Authors: Finlayson, G. & Hetherington, M.M., University of Leeds, UK.
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