Everything You Need to Know Before Going on a Low-Carb Diet  

Much like Oprah, we LOVE bread. So naturally, the thought of cutting it out of our lives (along with any other carbs) is terrifying. But then again, if everyone and their mom (and lots of scientific research) claim that quitting carbohydrates is the key to weight loss, there's got to be something to it, right?

Whether it takes the form of Atkins or the Paleo Diet, the low-carb trend has been around for a long time. But chances are you might not fully understand where it came from, how it works, and why experts are torn on whether this eating plan is smart. Here, we break down all of that so you can decide if carb-cutting in the name of weight loss is worth it.

What Low Carb Actually Means
Depending on who you talk to, there are different definitions of a low-carb diet. Plans can range from 100 grams of carbohydrates per day to zero grams (yikes), says Susan Kleiner, Ph.D, R.D., author of Power Eating. To put that into perspective, a small piece of fruit has about 15 grams of carbs and a banana contains up to 30 grams.

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For the sake of this article, though, we'll talk about a diet containing 100 grams of carbs per day, for someone who exercises three times a week at a moderate pace. For everyone else, a true low-carb diet would be about 50 grams per day, says Kleiner.

What’s Considered a Carb?
Unfortunately for Regina George, butter is not a carb. But according to the USDA’s Nutrient Database, lots of foods, including fruits and veggies, contain high amounts of carbohydrates. Though you probably know potatoes and bananas are packed with the carbohydrates, over 20 grams of the macronutrient are also found in a serving of grapes, apples, pears, and cauliflower. Plus, dried fruits, such as apricots, cranberries, and raisins, have a whopping 80 grams per serving. 

You’ll find carbs lurking in places other unsuspecting places, too. Frozen yogurt, almond and soy milk, barbeque sauce, and protein-packed beans and legumes (including chickpeas, kidney beans, and baked beans) are all considered high-carb foods.

How Low-Carb Diets Became Trendy
According to a 2008 article in the journal Epilepsia, the ketogenic diet, a high-fat, high-protein, low-carb diet, originated as a cure for epilepsy in 500 B.C. and is still used as such today.

The Atkins diet was invented in 1972 as a result of research aimed to help overweight people with hypertension, says Kleiner. Prior to Atkins, doctors were “starving” diseases in overweight patients with ultra low-calorie diets (500-600 calories a day). So when researchers discovered that a high-protein, low-carb diet was just as effective for weight loss, they started using this method so participants could have a normal caloric intake.

“Healthy eating shouldn’t be about deprivation.” 

The reason these diets have such staying power is because they do help people lose weight, says Keri Gans, R.D., author of The Small Change Diet. The thing is, people get frustrated with deprivation diets so they give up, she says.

Why Low-Carb Works Well for Some

No carbs means no-brainer portion control. Weight loss associated with a low-carb diet is mainly a result of eating less, says Albert Matheny, C.S.C.S., R.D., of SoHo Strength Lab and Promix Nutrition. “Carbs aren't bad, they're just over-consumed relative to a person’s activity level,” he says. When you cut carbs, you’re giving up the foods you might be overindulging in, which saves you tons of calories.

And it's easy to see why we can't stop, won't stop with the refined carbohydrates, says Matheny. Besides being super satisfying, things like cereal, spaghetti, and rice are cheaper, more convenient, and more frequently advertised than other foods, he says.

Plus, portion control is difficult for most people. “It's much easier to eliminate a food group than to learn how to eat it in a healthier way,” says Gans. If you’re a carb overeater, you’ll likely be cutting at least 20 percent of the food you consume, so of course you’d lose weight.

It keeps blood sugar in check. A high-carb diet leads to greater variations in blood sugar, says Matheny. These fluctuations make your body physiologically dependent on carbs, so you crave more and more each time your blood sugar drops. This leads to overeating and weight gain, he says. When you lower your carb intake, your blood sugar stabilizes, and your cravings are crushed.

More carbs = more water weight. Most of the weight you lose when you start a low-carb diet is water weight, says Gans. Fluctuating insulin levels found in many overweight individuals cause the body to retain sodium and water. And, according to a study published in The Journal of the American Hearth Association, a high-fat, low-carb diet stabilizes insulin levels, which leads to losing water weight and fat.

Why Low-Carb Doesn’t Work for Everyone

You over-consume other macronutrients. Because cutting out a chunk of your food intake leaves you hungry, many people will overeat other macronutrients that they’re “allowed” to have, says Matheny. The problem is, if you’re consuming 3,000 calories of fat and protein a day and burning only 1,500 calories, you’re still going to gain weight—regardless of the carb deficit.

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It isn’t sustainable. The chief problem with a low-carb diet is that people can't keep it up long-term. Both Kleiner and Gans agree that cutting out carbs completely, or even cutting back to 100 grams a day, is too difficult for most people.

“Giving up a food you love to eat almost always leads to feelings of deprivation,” says Kleiner. “If you feel deprived, there is no way you are going to keep up those eating habits.”

Your genes love carbs. You may be thinking, “But my sister-in-law’s cousin hasn't had bread in three years and swears by it!" But, Kleiner says, those who claim they worship at the low-carb altar for the long haul are either lying or genetically predisposed to not missing carbs.

It's true; studies have shown that genes can actually affect our taste preferences. And some people's genetically predetermined taste buds might lead them to fell 'meh' about carbs, says Kleiner.

Your body could respond poorly. If you eliminate carbohydrates, especially fiber-packed ones, like potatoes, quinoa, and fruit, you’re going to experience bloating and constipation from ousting them. Additionally, you could experience vitamin deficiencies and ketosis (a buildup of ketones in the body), which can lead to dehydration and insulin deficiency, says Gans.

It starts to affect your personality. Since carbs are energy fuel, you’ll probably feel a bit sluggish, says Gans. And if you really love the starchy stuff, eliminating your favorite foods will make you cranky as hell (in addition to not being able to poop).

What Girls Who Work Out Need to Know
While low-intensity exercises, like walking and yoga, take less energy and can be sustained without carbs, high-intensity workouts, like cycling and boot camp classes, require more fuel and are tough to take on without the help of carbohydrates in your diet, says Kleiner. (Start your physical transformation with Women's Health's Look Better Naked workout DVD.)

“Carbs are fuel for high-intensity activity,” says Matheny.

Your body on a high-intensity sweat sesh and low-carb diet: Trying a high-intensity interval-training class on a low-carb diet is a one-way ticket to the struggle bus. It's highly likely that you’ll feel like your effort is at a 10 when you’re only at a six, says Kleiner. That's because high-intensity workouts require energy from glucose stored in our muscles (which comes from carbs), says Matheny. When you run out of glucose fuel, these workouts begin to break down muscle, which is bad for your body and your metabolism.

Also, if you're just starting out on a low-carb diet, your blood sugar will drop as your muscles become active, which can lead to fatigue and dizziness, says Matheny.

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Your body on a low-intensity workout and low-carb meal plan: Since low-intensity workouts don’t require as much immediate energy, your body has more time to convert fat to fuel, says Matheny. 

Low-carb can lead to more effective fat-burning. That being said, a study published in the journal Metabolism found that ultra-marathoners (people who run 50 to 100 miles at once) experienced higher rates of fat burning when they capped carb consumption at 10 percent of their diet (for someone who eats 2,000 calories a day, that's 200 calories from carbohydrates or about two slices of bread). But since the study didn't measure actual performance, we don't know if the runners' workouts were their best or not.

Is Low-Carb Right For You?
Whether you should increase or decrease your carb intake depends on your personal goals, health, and lifestyle.

If you want to lose weight… Nutritionists and science agree that a low-carb, ketogenic diet can be helpful for weight loss if used as a short-term solution or jumping off point. The problem with diets like Atkins is that it forces you to make extreme and sudden lifestyle changes. That drastic change often leads to weight loss, much of which is from water weight. And when you start to return to a “balanced” diet, maintaining that weight loss becomes difficult. Plus, yo-yo dieting in this way can have serious consequences on your body and your relationship with food.

If you have health concerns… Both Matheny and Gans point out that if you're diabetic or hypoglycemic, low-carb could be useful in blood sugar control, but you should consult a registered dietitian before making any changes. If you have gastrointestinal problems, the lack of fiber might be an issue.

If you have #FitnessGoals… Unless you're sticking to low-intensity yoga, a low-carb diet isn’t the best option. High-intensity interval training is one of the most effective training techniques out there, and it requires a ton of carb-fueled energy. If you want to get better, faster, stronger (à la Kanye West), go ahead and eat a sweet potato a few hours before your HIIT workout.

“Carbs are fuel for high-intensity activity.”

What Is The Best Low-Carb Diet To Follow?
Let's get something out of the way right now: Following a strictly Paleo diet or obsessing over how many grams of carbs you eat per day is a recipe for weight-loss failure (not to mention an effed up relationship with food). Instead, it’s best to focus on they types of carbs you’re eating, says Gans.

“A healthy diet plan should include whole grains, fruit, veggies, and legumes—all of which are high-fiber carbohydrates,” says Gans. We’ve said it once, we’ll say it again: high-fiber foods can improve your digestion and help you lose weight by making you feel fuller, longer. “Learning portion control is key.” Your dinner plate should be 25 percent protein, 25 percent high-fiber carbohydrate and half vegetables, says Gans.

It’s fine to nix refined sugar and carbs (see: rainbow bagels, Lucky Charms, chips, and pasta) if you’re looking to cut back for a special event or as a general lifestyle change, says Kleiner. But as Matheny points out, even refined carbs have their place if you’ve got an activity level that can take it. Refined carbs before you work out can provide quick energy and can even improve your results.

Bottom line: “Healthy eating shouldn’t be about deprivation,” says Gans. 

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