Why Your Fat Cells May Not Love Breakfast

Eating breakfast has been billed as a good habit to support a variety of health benefits.1 Now there is more support for the value of a nutritionally favorable breakfast—at least for people with a healthy weight, based on a study,2 published in the Journal of Physiology.

Javier Gonzalez, PhD, an assistant professor of human physiology at the University of Bath, UK, who led the research, suggested that a typical breakfast can affect the body's fat cells by increasing the amount of sugar they take up. This process may reduce your risk of diabetes, although the study wasn’t designed to prove that point.2

The effect on fat cells and the increased uptake of sugar only occurred in lean people,2 says Dr. Gonzalez. The fat cells of individuals who were obese, with a body mass index (BMI) of 30 or higher, behaved differently in response to breakfast, his team found.

"Specifically, in lean people, breakfast appears to improve the sensitivity of fat cells to insulin," Dr. Gonzalez tells EndocrineWeb, "In other words, for the same amount of insulin available, fat cells will take up more sugar."  

Fat cells take up more sugar at breakfast in people who are lean.

A Closer Look at the Breakfast Study

“The researchers initiated the study in order to test the traditional advice that promotes a good breakfast as beneficial for weight control and overall health, which is based on observational information alone,” Dr. Gonzalez tells EndocrineWeb. So his team decided to test the effects of breakfast on all aspects of energy balance.

Dr. Gonzalez and his team assigned 49 adults (29 lean and 20 obese), to either eat a 700-calorie breakfast before 11 am, in which half the calories were eaten within two hours of awaking, or skipping breakfast and waiting until noon to eat the first meal of the day.2 On average, the lean group was age 36 and the obese group, age 43. The body mass index (BMI) of the lean group was 22.6; the obese, 33.

At the start and end of the study, the researchers measured the participants overall metabolism, body composition, appetite response and markers of cardiovascular health. They also measured each person's fat tissue level and analyzed the activity of 44 different genes and key proteins. Most interestingly, the researcher team studied the ability of fat cells to take up glucose in response to the insulin present.2

They found distinct differences.  In addition to differences in the rate that fat cells’ take up sugar in lean people who ate breakfast, they found that lean people who skipped breakfast seemed to burn more fat.

Applying the Findings Mean to Real Life Circumstances

The findings from this study add some valuable information about chronic fasting in comparison to eating breakfast every day, says Caroline Apovian, MD, FACP, FAC, professor of medicine and pediatrics and director of the Center for Nutrition and Weight Management at Boston Medical Center who wasn’t involved in the study but commented on the research for EndocrineWeb.

''The bottom line is that the way adipose tissue responds to fasting and eating breakfast is different in lean versus individuals who are obese," she says. "In people who are overweight, there is less glucose uptake by fat cells than in lean people when eating breakfast. This may be a compensation to reduce the amount of fat stored."

On the other hand, she says, “the research shows that when lean people fast, it revs up genes involved in fat metabolism, so they can burn fat more efficiently.” The same process wasn't seen in people whose weight is considered above a healthy range.

Despite the differences, she says, eating a good breakfast—that focuses on low glycemic foods and/or is high in protein—is still advised for everyone.1 This is important to reduce the risk of developing diabetes and heart disease.

Is Breakfast Still the Most Important Meal?

''From our study, some aspects of blood sugar control appeared to be beneficially affected by breakfast consumption," Dr. Gonzalez tells Endocrine Web, "Specifically, in lean people, regularly consuming breakfast seemed to maintain sugar levels that were more stable in the afternoon and evening, compared to the fasting group."

He can't, however, say which kind of breakfast would be ideal. In his study, most chose typical breakfast foods, such as cereals and juices, so it was high glycemic, carbohydrate-rich meal. The kind of breakfast chosen, he says, is likely to depend on your goals, and would need to be individualized. That is, he says, if you are highly active and lean, more carbohydrate-containing foods for breakfast would be good, but if you are sedentary, have (or at risk for) diabetes, that would not be a wise choice. Beyond that, more research is still needed to see if eating breakfast can actually result in a reduction in diabetes risk, he says.

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