What Is a Low-Carb Diet Plan? Benefits, Meal Plan and Food List
Cutting carbs can be a great way to shed a few inches from your waist. But what exactly is a low-carb diet? Find out more.
First things first: There’s no one low-carb diet – but many different approaches to low-carb eating.
Even with the Atkins diet, there are variations – including advice on how many carbs to eat daily. Generally speaking, low-carb diets take things like traditional pasta and bread off the plate. After all, one sandwich or a single serving of noodles could easily surpass the daily carb threshold. For example, with the Atkins 20, the original Atkins diet, you start out eating no more than 20 grams of carbohydrates 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.
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The paleo diet is 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. It has more recently become popular for weight loss, raising concerns among some health experts. The diet involves getting only about 5% to 10% of a person’s calories from carbs, while the lion’s share – around 70% to 80% – comes from fat and the balance from protein.
Dietary experts consider a diet where a person gets around or under 30% – or even in some cases 40% – 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 total macronutrients and calories consumed.
Most Americans actually eat more protein than necessary already. Although the recommended daily allowance, or RDA, for protein is 0.36 grams per pound daily, people over the age of 60 might want to shoot for 0.45 to 0.54 grams, according to recent research. This means that a 60-year-old female who weighs 170 pounds should aim to consume 70 to 84 grams each day. For reference, a 4-ounce cooked chicken breast contains 34 grams of protein, a ½ cup of cottage cheese contains 14 grams and a cup of milk contains 8.
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READ: Healthy Carbs to Eat. ]
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 have obesity.
“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.”
Gabrielle N. Gambino, a registered dietitian at New York-Presbyterian Hospital/Weill Cornell, explains that insulin is a hormone that supports our bodies’ mechanism for fat storage. In theory, low-carbohydrate diets should lead to decreased insulin circulation in the body. Eventually, if we don’t eat carbohydrates, which are our body’s preferred source of energy, we will run out of stored sugar (glycogen) to be used as fuel and our bodies will have no choice but to turn to our fat stores. This is why these diets lead to fat and weight loss, at least in the short term.
Although low-carb diets sometimes result in greater weight loss compared to other types of diet plans for the first few months, most long-term studies – those lasting one or two years – conclude that the weight loss incurred by low-carb eating is equivalent to pounds lost on other types of diets, including moderate-carbohydrate, low-fat plans.
For example, in a meta-analysis of more than 20 weight-loss trials including 1,063 people that lasted an average of 12 weeks, those on the higher-protein diets lost only an additional 1.7 pounds. When you cut fat or calories, you also usually slash your carb intake, and vice-versa. After all, the foods that are highest in carbohydrates, including pastries and French fries, are also rich sources of both fat and calories.
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 and flavorful meals to choose from is critical. For better – and worse too – a cottage industry has sprung up to provide oodles of low-carb options, from low-carb bread and low-carb pasta (like spiralizing zucchini and turning other veggies into noodles) to low-carb beer, 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 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.
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READ: The Best Vegetable Replacements for Carbohydrates. ]
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% of calories from carbs – and high-carb consumption, or getting more than 70% of calories from carbs, were associated with a higher rate of death from all causes.
The researchers point out that “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 finding suggests moderate carb consumption with plant-based substitutions may be safest.
So whether you get lots of protein and fat from foods like bacon and hot dogs or from 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 – 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 much of those benefits are lost if the diet is very high in animal protein and too low in vegetables, plant-based proteins or healthy fat from plants, according to Foroutan. In a study published by the American Heart Association, among 2,000 men between the ages of 42 and 60 followed for 22 years, those who ate the most meat, poultry and dairy protein had a slightly higher risk of heart failure compared to those who consumed less.
“Some studies have shown a short-term reduction in triglyceride levels, which are a main indicator of heart disease risk, yet other cardiovascular disease markers such as total cholesterol were unchanged after following a low carb, in comparison to other diets,” adds Gambino.
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 several 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.
“In terms of ketogenic diets (the very-low-carbohydrate diet plans), the long-term effects of this metabolic shift are yet to be completely understood. The body releases calcium stores when in ketosis, which may lead to issues with bone density. Furthermore, excessive protein intake may lead to kidney injury, if prolonged, in certain populations. People living with diabetes need to be careful when lowering their carbohydrate intake significantly, especially those on insulin regimens, improper dosing adjustments could lead to a life-threatening condition called ketoacidosis,” says Gambino.
Cooking animal protein – 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. Marinating your food, flipping the meat every minute as it cooks and avoiding overcooking will help reduce the dangers associated with grilled meat. Even so, the International Agency for Research on Cancer has stated that eating just 3.5 ounces of red meat each day raises colorectal cancer risk by 17%. Eating 2 ounces of processed meat daily increases the risk by 18%.
Gambino says that if patients request low-carbohydrate diets, she suggests “clients try to follow a Mediterranean, low-inflammatory diet in addition to their carbohydrate limits. This means avoiding fried, saturated, animal-based fats like bacon and sausage as much as possible and opting for oils and nuts as mainstay fat sources.”
When it comes to low-carb diets for diabetes management, some studies hint at improvements, but this eating plan poses risks. A low-carb diet is extremely restrictive, and some of those restrictions eliminate or severely limit healthy sources of nutrients and protein. For example, a one-half cup of lentils would put you over the daily limit for carbohydrate and halfway to the daily limit for protein in some keto diet plans.
“As with weight loss, there is a general trend reflecting improved metabolic effects and fasting insulin sensitivity in the short term but not necessarily a lasting effect over a year or more when compared to other diets. Again, the reason for this tapered effectiveness is unclear. Low carbohydrate diets tend to lack whole grains, and foods rich in whole grains have high fiber content – a main player in diabetes management,” says Gambino.
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SEE: Keto-Friendly Vegetables. ]
Should You Adopt a Low-Carb Diet?
While it’s certainly true that a diet full of refined carbohydrates and sugar can raise the risk of many health problems, including heart disease and diabetes, there’s no proof that carbohydrates are inherently fattening. And there’s no consensus on whether a low-carb diet is optimal 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.”
As for the hypothesis that low-glycemic carbs will inspire weight loss and prevent heart disease and diabetes, it’s important to keep in mind that when individuals begin to pay attention to the GI of food, they naturally begin to consume more fiber and produce while cutting back on refined starches and sugar. It’s not the low-glycemic diet that’s bringing about the positive health effects, it’s everything that comes packaged with a diet rich in these foods.
If your diet is rich in whole foods and devoid of processed foods already, adding a high-glycemic banana or sweet potato is unlikely to have a negative impact on your health. Furthermore, brown rice consumed with lean protein and nonstarchy vegetables will have less of a glycemic impact than brown rice consumed by itself.
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 recommend that people follow the Dietary Guidelines,” Yule says – including having carbohydrates comprise 45% to 65% of total calorie intake. After all, cutting out dairy can lead to deficiencies of both vitamin D and calcium. These nutrients are not well absorbed from plants such as leafy green vegetables.
Others worry that foods like whole grains will get short shifted. And removing whole grains from the menu will dramatically reduce the amount of fiber and vitamins in the diet.
Dietitians and health professionals advise tailoring the eating plan to the individual and determining what works for each person’s health goals. It also needs to be sustainable. To achieve that, experts recommend getting input from a dietitian – and talking with your doctor if you have any health concerns – to determine what’s best for you.
Foods to Avoid
If you choose to adopt a low-carb diet, you’ll certainly need to avoid or limit a variety of foods. Among other things, that includes:
- Bread.
- Pasta.
- Whole grains including rice, barley, quinoa and bulgur wheat.
- Beans and lentils.
- Potatoes, sweet potatoes, corn, peas, winter squash and carrots.
- Most fruits (berries and a few select others are sometimes allowed).
- Chips, crackers and pretzels.
- Juice.
- Cereal.
- Milk.
- Beer.
- Cake and pastries.
Of course, there are ultra-processed 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, nonstarchy veggies are fair game, though starchy vegetables such as sweet potatoes and corn, as well as legumes, are higher in carbohydrates.
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SEE: Fruits to Eat on a Low-Carb Diet. ]
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 including:
- Non-starchy vegetables like dark leafy greens, salad greens, mushrooms and crucifers, including broccoli, cauliflower and cabbage.
- Herbs and spices.
- Avocado.
- Nuts.
- Seeds.
- High-quality protein such as eggs, poultry, fish and pasture-raised red meat, or organic tofu and tempeh.
- Oils.
- Small amounts of fruit might be OK – berries, apples and citrus fruits are relatively low carb.
“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,” Foroutan adds.
There is no shortage of recipes and meal plans either, depending on the dietary approach you follow.
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 entrée 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.’ ”
The most important thing is that you clarify why you want to adopt a particular diet plan. If it’s only for weight loss, low-carb might not be the best or the only option available to you. Gambino explains, “Based on the literature, if you are looking for a short-term diet to lose some weight, say within 6 months, this may be a nice start to your wellness journey. If you’re trying to cut back on carbohydrates for diabetes purposes, this may help to improve your Hemoglobin A1C levels. However, I wouldn’t recommend cutting out extensive amounts of carbohydrates unless following a specific diet prescribed to you by a dietitian or other medical professional.”
The Best Foods for Weight Loss
Updated on Oct. 28, 2022: This story was previously published at an earlier date and has been updated with new information