Researchers asked whether adults in the United States who have a higher body mass index ate junk food, candy and soda more often. They used data from surveys done by the Centers for Disease Control and Prevention in 2007 and 2008 that asked 5,000 Americans to recall what they had eaten on two separate days.
There was no difference in how often Americans who are normal weight, with BMIs between 18.5 and 24.9, and Americans who are morbidly obese, with BMIs over 40, reported eating French fries, full-calorie sodas and desserts, the researchers reported. Overweight and obese Americans did not eat fast-food meals more frequently than the normal weight group.
Don't get too excited -- there are still health consequences to what we eat. But this might help people rethink what they cut out when they're trying to cut weight.
"It really was a surprise, I thought there would be a relationship" between how heavy a person was and how often they ate junk food, said David Just, professor of applied economics and management at Cornell University. Just is co-author of the study, which was published in the October issue of the journal Obesity Science & Practice
"The consumer takeaway is that people can probably find a way to eat healthy and include junk food sometimes. It doesn't have to be an all or nothing," Just said.
Overweight and obese adults also reported eating fewer salty and sweet snacks overall than normal weight adults.
"There's a possibility that people who have gained weight have started to cut back on these foods," Just said.
The findings should not be taken as carte blanche for people to eat all the fries, soda and desserts they want. These foods are linked to diseases such as diabetes and high blood pressure, and there could be individuals who are more likely to gain weight from eating junk foods, Just said.
"Passing up on junk food is a good idea, but it is probably not going to move the needle as much as focusing on the things you eat regularly," Just said. What will probably have a bigger impact on weight is how much you eat of those everyday foods and main dishes, and not the occasional junk food splurge, he added.
Reducing total calories eaten and the frequency of snacking might be the better dieting advice, the study said.
The researchers looked at whether people in the survey reported eating certain foods, rather than the amounts of each food they ate. It is possible that portion size is linked to weight, if not the frequency of consumption, and that overweight and obese Americans just eat more junk food when they do indulge, Just said.
The study also found that normal-weight Americans tended to eat fruits and vegetables more often than their overweight peers. This finding could suggest there is a difference in consumption of other food items between the BMI groups, and that thinner Americans ate more fruits and vegetables whereas heavier Americans ate more meat, potatoes, rice and breads, Just said. However, the researchers did not look at consumption of meat and starches in this study.
The researchers did not explore whether exercise could offset weight gain caused by junk food.
"If you're not active at all then eating junk food two to three times a week might be a problem for you, but if you are active it may not even move the needle," Just said.
Previous studies may have detected a relationship between frequent junk food consumption and higher BMI. The current study's authors said that might be because the studies included the very morbidly obese, who have a BMI greater than 44.9, and the underweight, who have a BMI of less than 18.5.
Although the study found that very morbidly obese people consumed soda and junk foods more often, they may have conditions that make them more prone to weight gain, Just said.
The new study excluded these two groups, which make up only 5% of the population, from their overall analysis.