Eating highly processed carbohydrates can have a similar effect on brain chemistry as addictive substances according to a study in the Journal of Clinical Nutrition. Stimulating regions of the brain involved with reward and craving, refined carbohydrates were found to cause excess hunger and overeating, leading the researchers to suspect limiting high-glycemic foods could be an effective method for discouraging obesity.
A public health crisis
Astoundingly, the rate of obesity in the U.S. has more than doubled since the 1970s. Food and Research Action Center states:
“Two-thirds of U.S. adults are overweight or obese (Flegal et al., 2012). In general, rates of overweight and obesity are higher for African-American and Hispanic women than Caucasian women, higher for Hispanic men than Caucasian and African-American men, higher in the South and Midwest, and tend to increase with age (Flegal et al., 2012; Gregg et al., 2009; Sherry et al., 2010). Research also shows that the heaviest Americans have become even heavier the past decade (Beydoun & Wang, 2009).”
If these figures are not alarming enough, 31.8 percent of children and adolescents are considered overweight or obese. Likewise, 30.4 percent of low-income preschoolers are overweight or obese. Since obesity is linked with diabetes, cancer, cardiovascular disease and a variety of other degenerative diseases, many experts are convinced this is the single most pressing public health crisis today. Fortunately, a research team at Boston Children’s Hospital may have discovered part of the solution: restricting processed carbs.
Curbing the trend
The team, lead by David Ludwig, MD, Phd, director of the New Balance Foundation Obesity Prevention Center, investigated how food consumption is regulated by the pleasure centers in the brain. “Beyond reward and craving, this part of the brain is also linked to substance abuse and dependence, which raises the question as to whether certain foods might be addictive,” said Ludwig in Science Daily.
To explore the connection, researchers documented hunger and blood glucose as well as information from magnetic resonance imaging (MRI) scans to determine brain activity during the four hour time frame following a meal – an important period as it influences eating behavior for subsequent meals.
Twelve overweight or obese men were given test meals in the form of milkshakes, each with the same calories, taste and sweetness. The only variance was that one contained carbohydrates that digested rapidly (high-glycemic) and the other slow digesting carbohydrates (low-glycemic). Participants who consumed the high-glycemic milkshake experienced a spike in blood sugar levels, followed by a severe drop within four hours. This crash in blood glucose triggered excessive hunger and activated the nucleus accumbens region of the brain – which is associated with addictive behaviors.
According to Science Daily, Ludwig believes “[t]hese findings suggest that limiting high-glycemic index carbohydrates like white bread and potatoes could help obese individuals reduce cravings and control the urge to overeat.”
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