Nutrition-wise blog

Fasting and food choices

By Jennifer K. Nelson, R.D., L.D. and Katherine Zeratsky, R.D., L.D. July 11, 2012

I talk to people about weight loss several times a week. People often tell me they skip meals. Cutting calories isn't the only reason people skip meals. They may skip eating because of hectic schedules, religious practices or financial reasons.

Skipping meals or fasting is safe on occasion, but it could undermine weight-management efforts.

Researchers at Cornell University describe what they found when they asked students to fast for 18 hours. After fasting, the students were offered a buffet that included dinner rolls, French fries, chicken, cheese, carrots, green beans and beverages.

Which foods were most popular? The starchy foods, such as dinner rolls and French fries, were consumed most and contributed most to overall calories. And vegetables were the least popular. In addition, people tended to eat more of the food that they started eating first.

Before we jump on the "carbs are bad" bandwagon, however, let's consider the facts and a theory. Starchy foods have a high energy density, meaning the calorie content is high relative to a small portion.

If your body thinks it's starving — for example, because you haven't fed it for more than 18 hours — these food choices make sense. They have a lot of calories for their volume, And that's appealing because your brain and body are telling you, "Stock up now, we may not get to eat again for 18 hours."

Vegetables, on the other hand, have a low energy dense. You can get serving after serving of them for relatively few calories.

What about the chicken and cheese? What role does protein play? The chicken and cheese were a close second in the foods chosen. Lean proteins, such as chicken without the skin, are moderately energy dense. Higher fat protein foods have a higher energy density.

Why does this matter? You can make these concepts work for you.

When you have times of feeling "starving" (fasting or not), put vegetables and fruits front and center. Don't rely on your sluggish carbohydrate-deprived brain to make a decision, let alone a healthy one. (Yes, carbs are you brain's preferred source of fuel.)

All foods play a role in satisfying our hunger. Making smart choices is one of the keys to better health. Give vegetables and fruits preferential treatment at your next meal and see if that changes how much you eat. Post your thoughts here.

To your health,

Jul. 11, 2012