Just like that old line about being hungry an hour after you eat Chinese food, new research is suggesting that indulging in that quick pick-me-up snack cake or cookie doesn’t satisfy your appetite – in fact, it makes you hungrier. Understanding why this happens may hold the key to weight loss and help those who suffer from Type 2 diabetes.
The results of a new study published in the American Journal of Clinical Nutrition, show that the quick spike and then crash in blood sugar which accompanies eating highly processed carbohydrates, “activates the reward and addiction centers in the brain”, and that “refined carbohydrates such as corn syrup could trigger food cravings not unlike the cravings that drug addicts experience.”
This is your brain. This is your brain on cake.
So what do we mean by refined carbohydrates? As a rule of thumb, think “white”, as in foods made with white flour and white sugar. Unfortunately, that includes just about everything in the cookie and bread aisle of your local market. But that also includes the sugars found in soft drinks (not only sodas), like white sugar and high fructose corn syrup. If the thought of dropping these foods from your meal plan makes you sad, there’s actually a reason for that. The massive blood sugar spike from these refined carbohydrates, available in so many foods, lights up the pleasure centers in your brain, rewarding you for eating them. Unfortunately, when blood sugar returns to normal, the brain seeks more, which is why the cravings resume and you’re at the bottom of the bag of cookies in no time at all. A cycle not unlike what drug addicts experience.
A Washington Post article on the study explains: “Study co-author David Ludwig, director of the New Balance Foundation Obesity Prevention Center in Boston and his colleagues gave 12 overweight and obese young men two drinks. One contained cornstarch, which has a low glycemic index, meaning it causes only a gradual rise in blood sugar. The other drink contained corn syrup, which has a high glycemic index. The researchers used artificial, zero-calorie sweeteners to make the two drinks taste identical.
“The men who received the high-glycemic-index drink showed a dramatic spike in blood sugar after consuming the drink. Four hours later, their blood sugar levels crashed, and they reported being very hungry.
“At the same time, brain scans of those who drank the corn syrup drink showed increased activation in the nucleus accumbens, a region of the brain that has been tied to reward and cravings in past research, compared with the men who drank the low-glycemic-index drink.”
Our bodies and brains evolved to seek out food wherever possible, consume it, and if necessary, store the calories in fat cells to guarantee our survival during periods where food may have been in short supply. The taste of “sweet”, which we call sugar, packed the most calories, so we ate it wherever we found it in nature – primarily in the form of fruit. Of course, in modern U.S. society few people are ever far away from a source of calories. Refined carbs are instant energy, a thousand times more calorie-dense than a piece of fruit, which makes the brain jump up and say, ‘yippee!”, followed by, “now get some more!”, as soon as the sugar buzz wears off. In evolutionary terms, our have-food-whenever-we-want-it society is a brand new development, one our bodies and brains have not yet adjusted to.
Study co-author Ludwig says, “The problem is when the modern, highly processed carbohydrates can hijack this evolutionarily based reward system, putting it, in effect, into overdrive. To put it simply, we didn’t evolve to eat the low-fat Twinkie for breakfast.”
Next time you’re hungry, reach for an apple.