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The Facts on Fat
It's not surprising that fat is surrounded by a negative aura; after all, it's the substance every dieter is trying to lose. But is all fat bad? What role does it play in the body? And when you actually lose it, where does it go? We consulted the experts and dissected the latest studies to answer your burning questions about the dreaded three-letter word.
Additional reporting by Brianna Steinhilber.
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Can Eating Certain Foods Help You Shed Fat?
While it seems counterintuitive, eating can actually help you burn fat and shed pounds — if you pick the right foods, that is. Foods that are high in protein, such as lean meats, eggs, nuts, and legumes, take more work to break down, so your body has to work harder (and burn more calories) to digest them. A study published in the 2005 British Journal of Nutrition found that increasing protein intake helped prevent weight regain after weight loss. And spicy foods like cayenne pepper might also have metabolism-boosting benefits. Not only does capsaicin, the compound that makes peppers hot, help to suppress appetite, but Purdue University researchers found that it can actually increase calorie burn and reduce cravings in dieters.
And believe it or not, eating fat can help you lose it. The Mediterranean diet, which emphasizes foods rich in omega-3 fatty acids like salmon, has been shown to increase satiety, thereby promoting weight loss. Most importantly, the Mediterranean diet is more effective at lowering your risk of heart attack than are low-fat diets.
Does Muscle Weigh More Than Fat?
This weight-loss cliché comes up over and over again, and the short answer is: yes. “Muscle does weigh more than fat, but when answering the question, it is important to remember that a pound is a pound, whether it's muscle or fat,” says John M. Kennedy, MD, director of preventative cardiology and wellness at Marina Del Rey Hospital in California and author of The Heart Health Bible. “The difference here is that muscle is much denser and more compact than fat. If you were to compare one cubic inch of muscle with one cubic inch of fat, the muscle would indeed be heavier.” Strength training and other weight-bearing exercises can help build muscle and keep you lean.
Does Muscle Actually Burn More Calories Than Fat?
This question sounds like a weight-loss myth, but it is, in fact, true. Muscle is designed for movement, so it burns energy at a higher rate than fat, which is used to store or conserve energy. That said, Kennedy notes that a pound of muscle burns about 7 to 10 calories a day when at rest, compared with 2 or 3 calories for fat. So don’t count on your new-found biceps to make or break your diet.
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What is the Best Exercise For Burning Fat?
“There really is no ‘best exercise’ for burning fat,” says Brian Quebbemann, MD, director of The NEW Program, an integrated bariatric program in Orange County, California. “However, the type of exercise that will burn the most calories is a workout that makes a muscle work so hard that it has to struggle to find enough calories in the bloodstream to continue performing.” Jogging, circuit training, and running up stairs are all good examples of fat-blasting exercises. To burn fat, you should aim to exercise at at least 70 percent of your maximum heart rate. Try working out with a heart-rate monitor to watch your progress, and keep in mind that exercising too hard can overwork your muscles, making them less efficient in burning calories.
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When You Lose Weight, Where Does It Go?
You may have heard recent rumblings that we breathe out fat. And in a way, this is actually true. “When a person loses weight, as long as he or she isn't starving, the body literally absorbs the fat,” Dr. Quebbemann explains. “Then the body converts the fat to carbohydrates that can be used as energy and metabolizes it into carbon dioxide, water, and heat.” Carbon dioxide is a gas that the lungs exhale.
Is It More Dangerous to Have Belly Fat?
Anyone who has struggled with weight likely has a problem zone where extra pounds tend to pack on. While this spot varies by individual, women tend to accumulate fat on the hips and the waist, whereas men more commonly store fat in their abdominal region.
Belly fat is thought to be particularly dangerous. Research has shown that this extra fat around internal organs is a bigger health hazard than weight gain in other areas. Not only does a larger waist circumference account for the increased incidence of type 2 diabetes among Americans, but normal-weight people who carry excess fat in the abdomen are at a three times greater risk of dying from heart disease, and two times greater risk of dying from any cause, than those of normal weight with a normal waist-to-hip ratio.
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Is All Fat Bad?
The answer is no. Your body contains two types of fat cells — white (in the right of the above image) and brown (in the left of the above image) — with vastly different purposes. “The job of a white fat cell is to store fat calories for future use,” says Aaron M. Cypess, MD, PhD, an assistant professor of medicine at Harvard Medical School. “White fat grows when we eat more calories. Ultimately, we get fat in two ways: our fat cells get bigger, and we also make more of them. The job of a brown fat cell is to generate heat. To do that, the cells store fat temporarily so that it can be used as a fuel source.” These brown fat cells — or "good" fat — have been linked to lower BMI and have a potential to increase metabolism. A study published in the 2009 New England Journal of Medicine found that the activity of brown fat was reduced in overweight men, making the role of brown fat in the body in relation to obesity an area of further exploration. A study published in the August 2015 issue of the journal Cell Metabolism found that white fat can be turned into brown fat. Further research is needed to identify exactly how this happens, which can potentially be used to develop drugs that can mimic the effect.
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Does Fat Have More Calories Than Other Nutrients?
“When most people think of a calorie, they equate it to something that causes you to gain weight,” says Kennedy. But really, a calorie is just a unit of food energy. “Humans use calories in the same way that cars use gasoline — to make them go,” Kennedy says. With that in mind, fat is the most calorie-dense of all nutrients, with 9 calories per gram versus 4 calories per gram for carbs and protein.
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Does Fat Have a Taste?
The latest discovery about the nutrient is that it may, in fact, have its own unique taste. For years it was believed that fat only added texture to foods, acting as a carrier of taste, but new research out of Purdue University reveals that fat may deserve a spot on the list next to bitter, sweet, salty, sour, and umami. The distinct taste, named “oleogustus,” was separately identified by participants who also recognized the other five tastes. The verdict? Not so tasty. Scientists hypothesize that the body may be programmed to like fats, but not fatty acids (the building blocks of fat). One possible explanation is that fatty acids accumulate in rotting foods as fat breaks down, serving as a warning to not eat something that might make you sick.
- Last Updated: 07/30/15
- Last Updated: 07/30/15