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  • Researchers say that it’s what, not how much, you eat that affects weight gain.
  • Nearly half of all Americans are obese, according to the most recent data from the National Health and Nutrition Examination Survey.
  • For years, many health experts have said cutting calories and exercising was key to weight loss.
  • Now, researchers say that advice can be flawed and misleading for people.

In a new article published in The American Journal of Clinical Nutrition researchers say how much we eat may not be to blame for obesity levels, but instead, it’s what we eat.

Nearly half of all Americans are obese, according to the most recent data from the National Health and Nutrition Examination Survey.

“The conventional approach to weight control, based on the Energy Balance Model, ‘eat less and move more,’ has utterly failed to stem the rapidly rising prevalence of obesity and related diseases,” lead study author David Ludwig, MD, PhD, an endocrinologist at Boston Children’s Hospital and professor at Harvard Medical School, told Healthline.

According to the Energy Balance Model (EBM), obesity is the result of eating too much or moving too little.

Surrounded by a dizzying selection of tasty, highly processed foods and an increasingly sedentary lifestyle, it seems inevitable that we gain weight.

But the study authors point out a flaw in this theory. Despite decades of public health messaging pushing people to eat less and exercise more, obesity rates and obesity-related diseases have continued to rise.

“Our paper proposes that the problem arises, not from such personal deficiencies per se, but rather from a fundamental flaw in how obesity is conceptualized,” Ludwig said. “We argue that the Energy Balance Model simply restates a law of physics, and lacks a focus on underlying causes, and on what’s driving the obesity pandemic.”

Ludwig said his team is presenting an “alternative biologically focused paradigm,” called the Carbohydrate-Insulin Model, in its most comprehensive form to date.

According to this model, it’s not overeating that causes obesity. It’s the body’s tendency to store excessive fat that makes us overeat, he said.

“We summarize the extensive evidence in support of the model, which has origins dating to the early 1900s,” Ludwig said. “We identify testable hypotheses that differentiate the models and consider their radically different implications for obesity treatment.”

“I wholeheartedly agree,” said Mitchell Roslin, MD, the chief of obesity surgery at Lenox Hill Hospital in New York City.

Roslin confirmed that it’s not how much you eat, but what’s actually on your plate that causes weight gain — particularly processed foods.

“Eating processed foods, especially those that are chemically altered and have fiber removed, trick the body,” he explained. “Despite leading to fat formation, the brain actually perceives an energy deficiency.”

Ludwig said, if the Carbohydrate-Insulin Model is right, it has “major implications” for obesity prevention and treatment.

“It means that a focus on what you eat,” he said, “rather than how much, could be more effective over the long term.”

Ludwig added that reducing consumption of processed carbohydrates, rather than restricting total calories, could make maintaining a moderate weight significantly easier.

Roslin said that most people with severe obesity are “poorly nourished, not super nourished.”

He pointed out that eating processed foods can lead to insulin resistance, which is a major problem rarely addressed by most physicians.

“As poor diet is continued, insulin levels rise to help control glucose and prevent diabetes,” he said. “The high insulin tells the body to store fat, especially in the wrong places, such as the liver. Triglycerides rise and heart disease [is] more likely.”

Roslin warned that this dietary pattern may eventually lead to diabetes, high blood pressure, and high cholesterol, which must be treated with medications.

“Yet the underlying cause, which is processed foods without fiber, is rarely addressed,” he said. Roslin also emphasized that, even with weight loss surgery, there must be a change in diet.

“Processed foods break the body’s thermostat,” he continued. “Surgery can correct and lower insulin levels. Yet returning to processed foods will break the new thermostat. Thus, eating less of the same is not a solution.”

“There is no doubt that all carbohydrates are not created equal,” said Sharon Zarabi, RD, the program director of Northwell Health’s Katz Institute for Women’s Health in New York City and Westchester.

She explained that simple carbohydrates, usually white, have been stripped of their nutrients, digest rapidly, and lead to a higher glycemic response.

Zarabi said that, while the glycemic index measures how quickly various carbohydrates turn into blood sugar in the body, it doesn’t take cooking method, serving size, or ripeness into account.

“A simple potato will have a different glycemic index when baked, steamed, made into a chip or curly fry,” she said. “Fats and proteins can also impact the glycemic index of any meal. Potatoes are usually eaten with butter, sprayed with oil, and accompanied with a steak or other protein source.”

According to Zarabi, this can significantly change a food’s total glycemic index, and its effect on blood sugar levels.

“It’s best to try and eat as close to nature as possible, including darker-colored, grainier foods that are minimally processed,” Zarabi said. “And, most importantly, enjoy what you eat.”

She said her rule of thumb is to look for foods high in fiber, which is 3 grams per serving or more, and containing less than 10 grams of sugar per item.

“Keep sugar to a minimum, as this is a source of empty calories, making it more difficult to lose weight,” Zarabi said. “This is a lifestyle. No short-term diet, surgery, or pill will outsmart the human body and its natural needs.”

Recent research finds it’s not how much we eat that causes obesity, but rather the types of foods we choose.

Experts say that processed carbs are stripped of nutrients and fiber, keeping us hungry while encouraging our bodies to store fat.

They also say it’s best to eat foods closer to their natural state, reduce dietary sugar, and increase fiber intake to maintain a moderate weight.