Yet another reason to not skip breakfast
06/18/13 11:24 AM
Loc: Seattle, WA
Skip Breakfast, Fuel Insulin Resistance
By Todd Neale, Senior Staff Writer, MedPage Today
Published: June 17, 2013
Reviewed by F. Perry Wilson, MD, MSCE; Instructor of Medicine, Perelman School of Medicine at the University of Pennsylvania and Dorothy Caputo, MA, BSN, RN, Nurse Planner
Note that this small cross-over study demonstrated that skipping breakfast may be associated with a less favorable insulin profile around lunchtime.
SAN FRANCISCO -- Overweight or obese women who did not eat breakfast had impaired metabolic responses after eating lunch, a small crossover study showed.
On the days the women skipped breakfast, there were greater spikes in insulin and glucose levels after lunch compared with those seen on the days the women only had water in the morning, according to Elizabeth Thomas, MD, of the University of Colorado School of Medicine in Aurora.
In addition, not eating breakfast was associated with significantly higher levels of free fatty acids before lunch because lipolysis was occurring, she reported at the Endocrine Society meeting here.
"It's possible that insulin resistance over time may predispose to further metabolic derangements and possibly progression to type 2 diabetes," she said, noting that longitudinal studies have identified a relationship between skipping breakfast and both increased weight gain and risk of type 2 diabetes.
"Learning about these mechanisms does give us better data to recommend eating habits to people, and I think our society is having trouble with eating habits," said Lisa Fish, MD, an endocrinologist practicing in Minneapolis and a member of the society's Advocacy and Public Outreach Core Committee.
Fish said that many people eat only one or two meals a day and then snack.
"People may be doing that to try and eat less but they end up with a dysfunctional use of fuel for their bodies that causes them to actually gain more weight and develop more insulin resistance," she said.
An estimated 10% to 20% of the population skips breakfast, and that practice has been associated with increased body mass index (BMI) in both adolescents and adults.
Some short-term studies -- mostly in lean individuals who habitually ate breakfast -- have looked at the metabolic effects of skipping breakfast and produced varying results: impaired insulin sensitivity; no change or an increase in energy intake; increased hunger; decreased satiety' and worse lipid profiles.
Thomas and colleagues explored the issue in a crossover study involving 10 women, ages 25 to 40 (mean 29), who had a BMI of 27 to 35 kg/m2 (mean 31.4). Eight of the women regularly ate breakfast and two regularly skipped the meal.
The study took place on 2 separate days, 1 month apart, during the follicular phase of the women's menstrual cycles. The women were told to not exercise the day before each assessment. The night before each study day, the researchers provided the women with a standardized dinner -- 15% protein, 30% fat, and 55% carbohydrates -- that provided 35% of the total daily energy requirements.
On the morning of the first study day, the women were randomized to either eat a standardized breakfast -- with the same macronutrient breakdown as the dinner the night before -- containing 25% of daily energy requirements or to consume only a glass of water. On the second study day, the women did the opposite.
Four hours after eating breakfast or drinking the glass of water, the participants were given a standardized lunch providing 35% of daily energy requirements.
Pre-lunch insulin levels were similar in both the breakfast and no-breakfast groups, but insulin levels increased to higher levels after lunch in women who did not eat breakfast that day. The area under the curve (AUC) was significantly greater in the no-breakfast group (P=0.001).
The findings were similar for glucose, for which the AUC was significantly greater in the women who did not eat breakfast that day (P=0.004).
The level of free fatty acids before lunch was higher in the no-breakfast group, and eating lunch resulted in a rapid drop. However, the AUC was still significantly higher in the women who skipped breakfast (P=0.03).
Fish noted that one potential limitation of the study was the use of a healthy breakfast with a mix of protein, fat, and carbohydrates, which doesn't reflect a typical American breakfast consisting mostly of carbohydrates.
"It may be helpful for [the researchers] to look, in addition, to things that are more realistic for what's actually going on," Fish said.
Thomas disclosed support from an NIH grant, an NIH/NCRR Colorado CTSI grant, the Endocrine Fellows Foundation (Fellows Development Research Grant Program in Diabetes, Obesity, and Fat Cell Biology), and a Colorado Nutrition Obesity Research Center Pilot Grant.
She did not report any conflicts of interest.
Primary source: The Endocrine Society
Thomas E, et al "Metabolic effects of skipping breakfast in obese women" ENDO 2013; Abstract OR09-2.
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