Don't Make Food Your Reward!

We all experience differences in weight loss success with some of us able to lose weight much easier than others.  In many cases, this can be simply due to differences in the amount of exercise we do; however, some research shows that these differences exist even when the exercise routine is supervised.  The reasons for this are not completely clear, but a new exercise and weight loss study suggests that differences in how we desire food after exercise might play a part in the individual differences in weight loss.

In this new weight loss study, which is free to download, obesity researchers examined exercise-induced changes in the perceived reward value of foods in overweight and obese volunteers.  Study volunteers followed a supervised exercise routine designed to burn 500 Calories per day, 5 days per week for 12 weeks.  The reward value of food was measured in each study volunteer using a computerized procedure that measured liking, wanting, and food preferences based on photographic food images that showed foods with different tastes and fat contents. Study volunteers were classified as Responders (exceeded predicted loss in fat mass) and Non-Responders (lower than expected loss in fat mass) and differences in their perceived reward value of food after exercise were examined at the start and end of the study.  The obesity researchers reported that:

• Responders lost an average of about 11 lbs in 12 weeks compared to Non-Responders who lost an average of 4 lbs.
• After a bout of exercise, the liking for all foods remained unchanged in Responders.  In contrast, Non-Responders experienced an increase in their liking for all foods immediately after an exercise session.  This perception in reward value of foods was similar at both the start and end of the study in both groups of volunteers.
• After an exercise session, Non-Responders showed a greater desire for high fat foods than Responders.
• Non-Responders experienced an increased preference for high fat, sweet foods immediately after exercise, while Responders showed an increased preference for low fat, non-sweet foods after exercise.

This is a fascinating study that concludes that overweight and obese individuals who show an increased desire for food, especially foods high in fat and sugar, immediately after an exercise session lost less weight.  One of the interesting aspects of this study is the fact that even individuals who successfully lost weight showed an increased desire for food; however, their preferences were for non-sweet, lower fat foods.  The obesity researchers also indicated that the preference for high fat, sweet foods after exercise in Non-Responders was only seen at the beginning of the study, suggesting that exercise if maintained regularly might be able to eventually overcome these preferences.  It is apparently unclear why some individuals experience a heightened desire for foods after exercise while others don't.  The study authors suggested that differences in brain hormones after exercise might sensitize some individuals to food and food cues.

This study shows the importance of not making food a reward for weight loss or exercise.  Of course, it makes sense to not use food as a reward because we often eat more than planned and defeat the purpose of exercise.  However, knowing that exercise might increase our desire for food makes it even more important to set up other reward systems.  For example if you meet an exercise goal, plan a relaxing day at the pool, beach or at the spa. Just make sure it is not food!

What reward system do you use?

Exercise in an important part of any good diet or weight loss plan.  My easy diet plan, which uses delicious high protein, low-glycemic bars and shakes, recommends walking 30-45 minutes a day as a great way to start exercising.  Tune in to watch me on QVC September 12th from 1 AM - 2 AM EST!