What Is a low-carb diet?

First things first: There’s no one low-carb diet — but many, many different approaches.

Even with the Atkins diet, there are variations — including the advice on how many carbs to eat daily. Generally speaking, low-carb diets often call for consuming no more than 20 carbs a day — taking things like traditional pasta and breads off the plate, where one sandwich’s worth of bread or a single serving of noodles could easily surpass that carb threshold. For example, with the Atkins 20, the original Atkins diet, you start out eating no more 20 carbs daily, while with the Atkins 40, you begin the diet eating 40 carbs or less per day; in both cases, carb consumption increases in later phases of the diet.

Another diet, the paleo diet — which is often thought of for sheer protein consumption — is, when looking across the macronutrient spectrum, low-carb as well. Then there’s the extremely carb-restricted ketogenic, or keto, diet. It’s been prescribed for decades to treat medical conditions like epilepsy and is used to manage Type 2 diabetes (along with other low-carb diets), and has more recently become popular for weight loss, raising concerns among some health experts. The diet involves getting only about 5 to 10 percent of a person’s calories from carbs, while the lion’s share — around 70 to 80 percent — comes from fat, and the balance from protein.

Dietary experts frequently say that a diet where a person gets around or under 30 percent — or even in some cases 40 percent — of their calories from carbs may be considered low-carb. But the total amount varies significantly by the approach taken, the individual and how much a person eats in regards to all macronutrients and calories consumed.

[See: The 14 Best Diets to Prevent and Manage Diabetes.]

Does a Low-Carb Diet Help You Lose Weight?

Research shows that low-carb diets can be effective for weight loss. A 2016 position paper from the Academy of Nutrition and Dietetics lists low-carb diets among weight-loss interventions for adults who are overweight or obese.

“I utilize and recommend low-carbohydrate diets in my practice all the time,” says Robin Foroutan, an integrative dietitian nutritionist based in New York City and a spokesperson at the Academy of Nutrition and Dietetics. “But the No. 1 important thing that we really stress is that the diet still has to be anti-inflammatory — and the way that you make your diet anti-inflammatory is to eat a lot of vegetables, utilize a lot of herbs and spices, choose very high-quality proteins, and cook those — the animal proteins — very low and slow, not high heat cooking.” Cooking meats — from beef to fish — at high heat can create chemicals in meat that “have been found to be mutagenic — that is, they cause changes in DNA that may increase the risk of cancer,” the National Cancer Institute notes.

As for sustaining weight loss, moderating carb consumption may help as well. The academy’s position paper notes that a low-carb diet is commonly defined as consuming not more than 20 grams of carbs daily, and then: “Once a desired weight is achieved, carbohydrate intake can increase to 50 grams per day.”

But longer term, as with many diets undertaken to lose weight, it can be difficult to stick with a structured approach, like a low-carb diet, experts say. “To me that’s more of a compliance issue,” says Eric Rimm, a professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health, of people gaining weight back over time after losing it on a low-carb diet. What’s more, Rimm says that while a low-carb diet can be an effective way to shed pounds, many who take a low-carb approach on their own, rather than following a plan prescribed to them, don’t do it in a healthy way over the long term.

Having a wide variety of high-quality foods, flavorful meals is critical. For better — and worse, too — a cottage industry has sprung up to provide oodles of low-carb options from low-carb bread to low-carb pasta (and ways to make substitutes, like spiralizing zucchini, and turning other veggies into noodles), low-carb beer to low-carb ice cream and even low-carb fast food. In other cases, adherents take liberties with meat — piling on animal fat and protein, while dialing down the carbs. Many of the substitutions miss the mark and can make losing weight much harder (if not impossible), while putting a person’s health in peril.

“Low-carb diets are not intended to be a bacon free-for-all,” Foroutan says.

Is a Low-Carb Diet Healthy?

Perhaps not surprisingly, what you’re replacing carbs with makes all the difference when it comes to results — and that extends to the potential effect the diet may have on your overall health. Recent research published in the journal The Lancet Public Health found that both a low-carb diet — or getting less than 40 percent of calories from carbs — and high-carb consumption, or getting more than 70 percent of calories from carbs, was associated with a higher rate of death from all causes.

The U-shaped curve suggests moderate carb consumption may be safest. “However, results varied by the source of macronutrients: Mortality increased when carbohydrates were exchanged for animal-derived fat or protein and mortality decreased when the substitutions were plant-based,” the researchers point out.

So whether you get lots of protein and fat from things like bacon, or that comes from things like nuts and avocados can make all the difference. “We really concluded that it’s not enough to focus on carbohydrates alone, but we really need to consider the types of foods replacing carbohydrates,” says lead study author Dr. Sara Seidelmann, a cardiologist, nutritionist and researcher at Brigham and Women’s Hospital and Harvard Medical School in Boston. Rimm was also involved in the research.

Low-carb diets appear to have benefits for cardiovascular health markers — lowering triglycerides, a type of fat found in the blood, increasing levels of so-called good, or HDL, cholesterol and helping with blood pressure control — but, says Foroutan who was not involved in the research, much of those benefits are lost if the diet is very high in animal proteins and too low in vegetables, or plant-based proteins and healthy fat from plants.

Based on observational data, when people in the western world adopt low-carb diets they tend to replace carbs with more animal fat and protein, which can increase risk of death in a range of ways, including by raising cardiovascular risk. “The reality is that in the U.S. and European populations, eating low-carb is primarily an animal-based endeavor,” Seidelmann says.

[See: 10 Lessons From Extreme Dieting.]

Should You Adopt a Low-Carb Diet?

There’s still no consensus on whether a low-carb diet is the optimal choice for weight loss — or if any diet is for that matter — and health concerns remain, especially with the most stringent versions. “Any of these diets can be nutritionally complete, but when people remove or severely limit a large number of foods in their diet, there is the potential for an increased risk of nutrient deficiencies,” says Summer Yule, a registered dietitian and health educator based in Avon, Connecticut.

Another concern is that diet plans that restrict or limit foods may lead people to fear certain foods or lead to disordered eating, or unhealthy, abnormal eating behaviors — something Yule says should be heeded: “If the person thinks that a diet approach may trigger disordered eating behaviors, they should not adopt the strategy.”

The latest Dietary Guidelines for Americans emphasize the importance of flexible eating patterns like the Mediterranean-style eating pattern (akin to a traditional Mediterranean diet) over rigid dietary plans, and focus on moderation. “In general, if a person is healthy (i.e. does not have medical conditions or take medicines that require certain dietary restrictions), I recommend that people follow the Dietary Guidelines,” Yule says — including having carbohydrates comprise 45 to 65 percent of total calorie intake.

Others worry that things like whole grains will get short shrift, though phased approaches to low-carb diets typically allow for these and a wide variety of foods to be worked back into the diet (if ever cut out) as a person continues on it.

But, dietitians and health professionals advise, rather than ruling out or in a diet for all, it’s important to tailor the approach to the individual, and to determine what works for that person’s health goals and is sustainable. To achieve that, experts recommend getting input from a dietitian — and talking with your doctor as well if you have any health concerns — to determine what’s best for you.

Foods to Avoid

If you should opt to adopt a low-carb diet, you’ll certainly need to take a close look at what you should generally avoid or limit. Among other things, that includes:

— Breads

— Chips

— Crackers

— Added sugar

— Juice

— Cereal

— Milk

— Beer

— Cake

— Starches like corn and potatoes

Of course, there are low- or no-carb varieties of just about everything. But just because something is labeled low-carb doesn’t mean it’s healthy — so read the label first. On the other hand, veggies tend to be fair game, in general, though it requires more planning to stay within a set parameter since starchy ones and other plant-based foods like beans can be higher in carbs.

Foods to Eat

Rather than getting hung up on what to avoid, Foroutan says she likes to focus on what people should eat more of. That includes:

— Non-starchy vegetables like dark leafy greens, salad greens, crucifers like broccoli, cauliflower and cabbage

— Mushrooms

— Herbs and spices

— Avocado

— Nuts

— Seeds

— High-quality protein such as eggs, poultry, fish and pasture-raised red meat, or organic tofu and tempeh

“If your plan allows for fruit, berries, kiwi, apple and grapefruit are generally great choices — high in antioxidants and lower in sugar than many other fruits,” she adds.

There is no shortage of recipes and meal plans either, depending on the dietary approach you follow.

[See: The 12 Best Diets for Your Heart.]

Eating Out on a Low-Carb Diet

Going to a restaurant? You can still stick to the plan.

Here are a few ways Foroutan suggests doing that:

“Avoid the bread basket — it is not your friend,” she advises. “If you can get your group on board, don’t even let the server put it on the table. Some restaurants will serve cut up vegetables instead of bread if you ask.”

Keep it simple. “That does not mean bland, because herb sauces like pesto and chimichurri, and spicy rubs or marinades are full of flavor and generally don’t add carbs.”

Focus on veggies and protein. “Salad starters are always available, and look for simply prepared main dishes on the menu, like rotisserie or roasted chicken, grilled or poached fish, steak or lamb chops,” Foroutan suggests. If the entree comes with a vegetable and starch, ask if you can swap the starch for a larger serving of the vegetable. “So many restaurants now offer creative and flavorful vegetable sides, so keep an eye out for those kinds of options on a menu,” she says. “Even many Italian restaurants are getting on board by offering zucchini ‘pasta.'”

Eating in or out, experts reiterate: Pay attention to what you add into your diet, not just what you take out.

More from U.S. News

6 Healthy, Complete Meals You Can Make in the Microwave

Should You Count Calories or Track Macronutrients?

8 Food Trends Nutrition Experts Pray Will Never Return

What Is a Low-Carb Diet? originally appeared on usnews.com

More from WTOP

Log in to your WTOP account for notifications and alerts customized for you.

Sign up