February 4, 2013

202 Obesity & Food Cravings [4 February 2013]

A recent study shows that the brains of overweight people react differently to the sight of food than those of their normal weight friends.

Researchers from the University of Southern California Keck School of Medicine used functional MRI to observe brain activity in 5 obese and 7 normal weight adults at different blood sugar levels. The subjects were shown pictures of high calorie foods, low calorie foods, and non-food items at different glucose levels and asked to rate their hunger and desire for the food.

As would be expected, both obese and normal weight subjects reported more hunger and desire for high calorie foods at hypoglycemic (low blood sugar) than at euglycemic (normal blood sugar) levels. Correspondingly, while hypoglycemic, both groups showed higher brain activity in the hypothalamus and limbic brain (which initiates cravings for food to replenish blood sugar). When the blood sugar levels were returned to normal, the normal weight group had higher activity in the prefrontal cortex (which controls rational decision making), and the desire for food fell. This didn’t happen in the obese group – the activity remained high in the hypothalamus and hind brain and the cravings for food was not alleviated. This explains why it is harder for obese individuals to eat appropriately to lose or even maintain weight, something their normal weight friends often fail to comprehend.

Here is what I think this study means to someone who is overweight:
• there is a physiological explanation for your cravings – it’s not just a character weakness;
• eat more frequent small meals to keep your blood sugar levels even and to reduce cravings and subsequent overeating;
• avoid visual cues of food between meals (hide the cookie jar);
• once you have lost your excess fat weight it will be easier to keep it off.

Source: “Circulating glucose levels modulate neural control of desire for high caloric foods in humans”, J Clin Invest 121(10), October 2011.

For more information on this or other natural health topics, stop in and talk to Stan; for medical advice consult your licensed health practitioner.

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