Study disproves stereotype that obese people lie about how much food they eat – Reuters


ROCHESTER, Minn. — For years, researchers have reported that people tend to underestimate the number of calories they eat, and obese people tend to underestimate the calories they eat the most.

But a new study by researchers at the University of Essex has shed light on what can really happen when tall people underestimate how much food they eat. He finds that the error is not at all specific to anything unique to obese people.

Calorie undercounting is a problem for the food status quo, as health workers and nutritionists believe their jobs require them to ask people how much they eat – data generally considered unreliable.

As recently as 2019, an article in the

Journal of Health Psychology

identified 34 studies

showing that “having a body mass index greater than 30 is associated with significant under-reporting of food intake”.

This paper listed variables associated with inaccurate calorie counting in obese people, including gender (female), desire to lose weight, less realistic weight loss goals, and low education.

But others have argued for years that “the mechanisms responsible for the phenomenon are not well understood,” as Columbia University researchers wrote in the

New England Journal of Medicine in 1992.

These scientists said the problem of calorie underestimation in people with high BMIs did not appear to be a problem of deception, as the people they studied “were upset” when told of their mistake. .

According to the authors of the new research, as reported in the

American Journal of Human Biology

, underestimating your calories is a common process of being off by a standard percentage. In the context of the high calorie needs of active, younger or high body mass index people, this is an error that increases in absolute terms.

“A widely accepted narrative is that people who are obese lie about their food intake because they are likely to have negative perceptions of their body image…and are more likely to periodically restrict food,” Sally said. Waterworth, co-author and lecturer at the School of Sport, Rehabilitation and Exercise Science at the University of Essex, told Forum News Service.

“We wondered if this story was correct, or if the greater under-reporting among obese people is simply because as energy requirements increase with larger body size, there are more mismatch between what people report and what they actually eat.”

Waterworth and colleagues recruited 221 British participants in a government dietary intake survey and then sorted them by age and level of physical activity.

Using a sophisticated method of measuring energy expenditure, they were able to compare calories reported as consumed to actual calories burned while remaining stable in terms of weight – actual calorie intake.

They learned that people with high BMIs did indeed underestimate the amount of food they ate – by 1,300 calories on average, compared to just under 800 calories for people without obesity. But they also found that athletes and young people underestimated their intake by the same amount.

“Everyone is underreporting, let’s be clear on that,” Waterworth said of the finding. “But when you control for body weight, we all underreport the same thing.”

Calorie goals are to blame

The authors believe the problem starts with having universal recommendations for daily calorie intake, goals that are unrealistic for everyone, but counterproductive for obese people.

“Simply having energy intake recommendations for everyone doesn’t make sense,” said Gavin Sandercock, co-author and professor of exercise science at the School of Sport Science, Rehabilitation. and exercise from the University of Essex, in an interview. “A very simple thing would be to adjust them to your size as well as your level of activity. But it’s your size that is more important.”

The authors learned that the typical person in the UK reports eating around 1,800 calories a day, regardless of height. Although they didn’t research the issue, the authors thought the figure was likely anchored around the government’s calorie targets of 2,000 calories a day for women and 2,500 for men.

In the United States, calorie goals are similar, but presented in ranges.

“I couldn’t live on 1,800 calories,” Sandercock said. “I couldn’t even sleep all day on 1,800 calories. No man my size could… It’s definitely not enough for them to live and meet activity guidelines.”

“We really question the validity of the tool,” Waterworth said, “if it should be used and if it really matters because it’s so far removed from reality.”

His advice is for health officials to ditch the numbers and “focus on the food.”

“Obese people are mislabeled in many ways,” Sandercock said. “But this is the first time we’ve seen them labeled as liars.”

“It’s just not helpful. Shame is not a way to get people to be healthier. From a scientific perspective, trying to blame a methodological problem on a subgroup…it’s irresponsible.”

“They would have been better off blaming the athletes and the active people,” Sandercock said. “I wouldn’t mind being blamed. I know I eat a lot.”


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