November 21, 2012

Calories 201

A new study shows that kinds of calories you eat can make a difference.

Jessica: A new study finds that some foods can help you burn more calories than other foods, and that could have a major impact on those who are trying to stay in shape. But before we get to that, let’s go back to basics and see just how much you know about calories in a pop quiz.

Now calories are a unit of measurement. So what does a calorie measure? Is it:

A. Volume

B. Mass

C. Energy

D. Weight

You have got ten seconds!

The right answer is “C,” energy.

I went to Columbia University to find out more about calories.

Pamela Koch: So, a calorie is a unit to measure energy. It is precisely the amount of energy it takes to raise on milliliter of water one degree Celsius.

Jessica: But the calories in food are called large calories or kilocalories, one large calorie equals the amount of energy it takes to raise one kilogram of water one degree Celsius.

Armed with that calculation, we decided to measure the amount of calories in one peanut.

Pamela: We are then trying to see how much this one peanut is able to heat up water. And so we have in here, in this beaker, we have 50 milliliters of water. And what is the temperature right now?

Jessica: I think it is about 28-degrees Celsius, which is about 82-degrees Fahrenheit.

Pam: Ok, so now what we’re going to do is we are going to light the peanut on fire. The peanut will only light on fire because the energy in the peanut can be ignited and, basically, the fire will only burn as long as there is energy in the peanut.

So the peanut just went out, and that means that all the energy that was in the peanut has been consumed by the fire. So let’s look at the temperature now.

Jessica: It is about 50-degrees Celsius.

Pamela: So that means that this one peanut was able to raise these 50 milliliters of water about almost 30-degrees Celsius.

Jessica: That is a lot.

Pamela: So you can see how much energy is in there.

Jessica: Well, peanuts. That means that the peanut has a lot of energy, and nuts are supposed to have a lot of calories.

Pamela: Right, it would come out that the peanut has about five to seven or eight calories, which for one peanut is about what the peanut would have.

Jessica: Got it. Cool! Very cool!

But eating 100 calories of peanuts may not be the same as eating 100 calories of cookies. We will explain next.

Many people think all calories are created equal but new research is challenging that idea. So what foods are best for staying fit? You may be surprised by the answer.

Researchers at Harvard University divided up participants into three different groups. Everyone ate the same number of calories, 1600. But one group followed a low fat diet, where most of the calories came from carbohydrates like whole grains, fruits and vegetables.

The second group followed a low carb diet. The majority of calories came from proteins and fats.

The final group followed a low glycemic diet. Low glycemic foods are foods that take a longer time for the body to absorb and that do not cause blood sugar levels to spike. These are foods like low fat dairy products, nuts and leafy greens.

After one month, researchers found the three diets produced very different results.

Those on the low carb diet burned the most calories, 150 more a day than the low glycemic, and 300 more calories a day than those on the low fat diet.

Researchers say this study suggests a very low fat diet can actually slow down a person’s metabolism, causing them to not burn as many calories and ultimately gain weight.

Kerry Monaghan: I mean, for me, that’s really counterintuitive because I’ve always thought eating low fat is the way to go. On the low fat diet, it actually didn’t perform very well at all.

Jessica: Kerry Monaghan is a nutrition coach.

So fat is not bad!

Kerry: Fat is not bad and fat doesn’t make you fat.

Jessica: So why does the U.S. government recommend a low fat diet?

Kerry: The government has been recommending a low fat diet for the past 30 years. And honestly, in that time we’ve seen a huge increase in all of these chronic health problems, like obesity and diabetes.

Jessica: People on the low carb diet, they are the ones who burn the most amount of calories. So would you recommend this type of diet?

Kerry: People did burn a lot of calories but they did see some problems on that diet as well. There were some indicators for disease. So I wouldn’t really recommend that for the long-term.

Jessica: But Kerry and the researchers behind the Harvard study give a thumbs up to the low glycemic diet.

Kerry: You’re choosing foods that are going to keep your sugar levels really steady so you won’t have that spike and the crash. We have our beans, our lentils, lots of vegetables. It’s the non-starchy vegetables. So something like a sweet potato or a white potato is going to be higher glycemic. But your leafy greens and your broccoli, those are all lower glycemic.

Jessica: The overall finding of this research is that 200 calories of, say, junk food acts differently in your body than 200 calories of broccoli.

Kerry: Yeah. A lot of people think that if they want to lose weight they just need to cut down on their calories. But what we know now is that if you’re having 200 calories worth of candy, they’re going to spike your blood sugars. And then what happens with those sugars is some of them will get stored in your liver and the rest, the excess sugar, is going to get stored as fat.

When you’re eating something like broccoli, it has a lot of fiber. So it takes a long time to digest. So what happens is it actually keeps you full for longer and you’re not going to have that spike in your blood sugar and then a crash.

Jessica: Now, critics of the glycemic index say it can be confusing and point out foods affect people differently. But most experts agree, foods that are close to the farm are better, meaning foods that are not processed, where you can recognize and pronounce all the ingredients.


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