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14 Questions Nutritionists Get Asked the Most

Is gluten-free food healthier? Is low-carb the only way to lose weight? Is sugar the devil's food? You have questions. We have expert answers.

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We asked so you didn’t have to

It seems little is more complicated or contradictory than diet advice these days. Ask 20 people about the best diet and you’ll get 25 different opinions. So to help you separate fact from the fiction and get answers to your burning questions, we asked nutrition experts about the questions they get asked the most and what they really want you to know.

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Do I have to cut carbs to lose fat?

Demonizing carbs is popular in the diet industry these days and high-fat diets are touted as the best way to burn fat, but while this may work in some cases it’s not the whole story, says Rachel Fine, RDN, owner of To The Pointe Nutrition. “Yes, fat oxidation (burn) will increase if the majority of one’s dietary calories are coming from fat, however, the increase is accompanied by a subsequent increase in fat stores,” she explains. “Biologically, the body prefers to burn carbohydrate, especially in the presence of physical activity. Fat and carbs go hand in hand—the metabolites produced from carbohydrate metabolism are needed for fat metabolism.”

Bottom line: To reach and maintain a healthy weight, bodies need a balance of carbohydrates, protein, and fat. When it comes to carbs, she suggests choosing minimally processed plant-based sources like whole grains, legumes, nuts, and seeds. Look out for these silent signs you should eat more carbs.

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Is sugar really the worst?

Sugar isn’t the horrible thing many people make it out to be, but it definitely needs to be eaten in moderation, Fine says. “Technically, sugar is the simplest form of one of the major macronutrients: carbohydrates. Carbs are critical for the body, providing the most efficient form of fuel,” she explains. The problem starts when sugar is ultra-refined, processed, and added to other foods (i.e. high fructose corn syrup), but sugars found naturally in whole foods like fruit and dairy are just fine, she says.

Bottom line: Reducing the amount of added sugars in your diet is key, she says. Read the nutrition labels, as they are now required to show what type of sugar is in food.

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What diet will help me lose weight the fastest?

This is a trick question, says Julie Cunningham, MPH, RD, and certified online diabetes educator. Why? People need to stop seeing a “diet” as something they start and stop and quit focusing on fast weight loss, she says. “An extreme diet is likely to be short-lived and result in a short-term weight loss with even more weight regained after the diet ends,” she explains.

Bottom line: Focus on making healthier food choices a permanent change in your lifestyle, not a short term “diet” that you’ll quit when the scale gives you the number you want, she says. To change your thinking, discover the power of mindful eating.

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Should I try the keto diet?

“I get this question all the time these days but the answer depends entirely on the ‘how’ and the ‘why’,” says Laura Acosta, RD, lecturer in dietetics at the University of Florida. “Overall, I think that a truly ketogenic diet [one that gets 70 percent or more calories from fat and has so few carbs that it sends the body into a state of perpetual ketogenesis] is extremely restrictive and difficult to sustain long-term. However, there are many ‘pseudo-keto’ diets that are low-carb, but not actually ketogenic and these are potentially easier to sustain,” she explains.

Bottom line: There are conditions for which a true ketogenic diet is entirely appropriate—for instance, it’s been proven in gold-standard studies that it can help control seizures in pediatric epilepsy—however, if your goal is weight loss, there are far less extreme measures, including several popular “keto” plans, you can use that to help you lose weight without putting your body through so much stress, she says. Find out the 12 things that happen to your body on the keto diet.

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Is fruit fattening?

Many popular diet plans these days tell people to only eat “low sugar” fruits, like berries, or restrict fruits entirely. But is it really true that bananas are diet busters? “I get this question all the time,” says Kimberly Gomer, RD, director of nutrition at the Pritikin Longevity Center + Spa. “I always reply, ‘Do you really think so many people struggle with weight because they eat too many bananas?’,” While people who have trouble with high blood sugar or are insulin resistant, such as diabetics or those with PCOS, may need to watch the even natural sugars in some fruits, most people can eat a banana every day without worry, she says.

Bottom line: Fruits are whole foods, and while they do contain sugar, it comes with lots of fiber, which slows digestion, as well as important vitamins and minerals. Think about reducing added and processed sugars from your diet before you worry about fruit, she says.

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I worked out for an hour so now I can have whatever I want for dinner, right?

“I run for cake” may be cute on t-shirts, but diet math is often more complicated than that, Gomer says. For instance, the “calories burned” displayed on exercise machines is often highly inaccurate. In addition, people are notorious for underestimating how much they eat and overestimating how much they exercise. “We sometimes think we can make up for unhealthy food choices by exercising, but that can lead to exercising too much which can cause injuries and increase your hunger,” she explains. “It’s just way too easy to out-eat your exercise.”

Bottom line: “If your goal is to lose weight then you need to create a caloric deficit,” she says. “The best way to do this is to focus on healthy food choices and a sustainable plan that includes exercise but doesn’t rely on it to cut calories.”

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What’s the absolute worst food people eat?

When it comes to poor health and obesity, the worst food isn’t a food—it’s a drink, says John La Puma, MD, nutrition expert, co-founder of ChefMD, and author of REFUEL: A 24 Day Plan to Shed Fat. If he could ban one item from people’s diets it would soda. “One Coke has 16 teaspoons of sugar per 20-ounce bottle, that’s a full 1/3 cup of straight sugar,” he says. “Stop drinking your calories; there is no nutrition there, and it doesn’t fill you up, making it harder for you to recognize when you’re satiated.” Find out what happens to your body an hour after drinking a can of soda.

Bottom line: Ditch the soda. And be conscious of calories in all your drinks, he adds.

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How many calories do I need to eat lose weight?

Slashing your daily intake of food to the “recommended” 1200 calories you see in many diet plans will make you lose weight fast. Unfortunately, it will also likely leave you starving, grouchy, and ready to fall off the wagon the second you see a cupcake. Caloric needs are very individual, and it’s worth your time to figure out yours, says Charlie Seltzer, MD, a weight-loss physician and exercise physiologist in Philadelphia. “The simple answer is if you want to lose weight then you need to eat less than you’re eating now,” he says. Equations that take into account your gender, height, weight, age, and activity level can give you a ballpark number, but don’t stop there—track your food and note how your weight responds, he says.

Bottom line: “I recommend tracking all your food for a week, then cutting 5 to 10 percent of those calories,” he says. “You’ll have more success by tweaking your current diet, not by trying to completely overhaul it.”

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How can I lose my belly fat?

Sorry, but all those internet ads suggesting you can spot train are just outright lies. When it comes to weight loss, you don’t get to pick and choose where you reduce, says Susan Bowerman, RD, senior director of nutrition education and training at Herbalife. “I tell my clients that when they lose weight, they should expect to have a similar silhouette—that they will be basically the same shape they are, only smaller,” she says. ” Heredity and gender determine where body fat is stored.” That said, this shouldn’t discourage you from trying to be the best “you” that you can be, she adds.

Bottom line: A combination of a well-balanced, calorie-controlled diet coupled with an exercise regimen that includes both cardio and strength training is the best way to uncover your personal ideal shape, she says. Still struggling with your middle? Try these 27 tips to help you get your best waist.

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What is the best diet out there?

“The best diet for you is the one you can stick to,” Dr. Seltzer says. Trying to make a rigid diet plan fit your lifestyle is just setting yourself up for failure; instead, find a healthy plan that works with your life and tastes, he advises. “This means that if you plan on doing something for the rest of your life, like drinking alcohol, then make sure it is part of your weight loss plan. Eliminating drinking until you hit your goal weight, then reintroducing it backfires most of the time,” he says. P.S.: It’s just one of the 50 things your doctor wishes you understood about weight loss.

Bottom line: Any plan that results in a calorie deficit will work over the short term, but if you don’t want to gain the weight back, find a plan you can live with over the long run, he says.

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Why is healthy eating so expensive?

“It isn’t!” says Christopher Dalmau, a nutritionist, exercise physiologist, and founder of The Clean 5, adding that he hears this popular myth from clients all the time. In fact, eating healthfully can save you money on your grocery bill right now—and save you even more by avoiding future medical bills, he explains. Unhealthy diets, which included routine alcohol consumption, were much more expensive than their “healthy” counterparts, according to a recent study out of Australia. “I suspect the reason I am often asked this question has to do with the public perception of ‘healthy food’,” he says. “When I talk about healthy foods, I mean whole, unprocessed foods. These foods fill us up and definitely aren’t expensive.”

Bottom line: Skip the expensive premium “health food” products like packaged powders, drinks, bars, and supplements and instead build your menu around in-season, sale-priced whole fruits, vegetables, nuts, legumes, grains, dairy, and meat. Hint: Those expensive bars are one of the 13 weight-loss products nutritionists never buy and neither should you.

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What is the best food a person can eat?

This is an easy question to answer, says Jackie Newgent, RDN, author of The All-Natural Diabetes Cookbook, and spokesperson for KIND Snacks. Her verdict? You can never go wrong with lots of non-starchy vegetables. “I advise aiming to fill half of every mealtime plate or bowl with vegetables like spinach, asparagus, tomatoes, mushrooms, peppers, broccoli, cauliflower, kale, zucchini, or salad greens,” she says. “Yes, even at breakfast-time!” It’s also backed by science: Eating more vegetables can help you lose weight and manage your blood sugar, according to a study published in Nutrients.

Bottom line: There’s a reason vegetables are the common variable in every single diet out there. Veggies are packed with fiber and nutrients, they fill you up, and you can eat as many as you want for very few calories.

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Should I snack or not?

On the one hand, you hear it’s good to eat every two hours to keep your metabolisms revving and to keep yourself from getting so overly hungry that you lose control. On the other hand, you also hear that it’s best to cut out all snacks and “fast” for a certain number of hours every day. If you’re confused about how often to eat, you’re not alone, Newgent says. “Snacking may help fill in nutrient gaps, keep you satisfied, and potentially prevent overeating at mealtime,” she says. Her favorite snacks combine a protein with produce, such as hummus and veggies or nuts and fruit.

Bottom line: Snacks should be small portions, but some people overeat them. If snacking is a trigger for you, don’t do it. Bottom line, it’s best to eat when you’re hungry; abstain when you’re not. Every person needs to find what works for them personally. Here are 30 of our favorite snacks.

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Should I go gluten-free?

Gluten, the protein found in grains like wheat and barley, has gotten a bad rap—and that’s a shame, says Monica Auslander Moreno, RDN, consultant for RSP Nutrition. “Whenever someone asks me if they should go gluten- or dairy- or whatever-free, I point out that just because it’s a trend does not make it appropriate for you,” she explains. “There are certainly medically indicated reasons for these ‘elimination diets’ but it is not prudent advice for the general population, and can actually result in nutrient deficiencies, disordered eating, and microbiome disturbances when certain proteins like gluten and dairy are cut out.”

Bottom line: Unless you have a medical condition that prohibits eating a particular food group, there is no need for you to cut it out, she says. Next, read on for the 19 ‘healthy’ food rules nutritionists regularly ignore.

Charlotte Hilton Andersen
Charlotte Hilton Andersen is a health, lifestyle and fitness expert and teacher. She covers all things wellness for Reader’s Digest and The Healthy. With dual masters degrees in information technology and education, she has been a journalist for 17 years and is the author of The Great Fitness Experiment. She lives in Denver with her husband, five kids and three pets.