A low-carb diet restricts your intake of foods containing carbohydrates. Food like pasta, bread, starchy vegetables and sugar will be extremely limited. How restrictive you will have to be with your carb intake depends on your current carb intake, activity level and weight-loss goals.
Types of Low-Carb Diets
The standard nutrition recommendation from the Dietary Guidelines for Americans is to get 45 to 65 percent of your daily calories from carbohydrates. For a basic 2,000-calorie diet, this amounts to between 225 and 325 grams of carbs per day.
There are several types of low-carb diets. The most popular is the keto diet, a very-low-carb diet that restricts your carb count down to 20 grams per day. Other moderately low-carb diets allow between 100 to 150 grams of carbs per day.
A very-low-carb diet usually pushes you into a state of ketosis, in which your body burns fat more efficiently and produces chemicals called ketones to fuel your brain in the absence of carbs. A ketogenic diet features a high-fat and moderate protein intake and is often accompanied by an uncomfortable phase-in period during which you experience side effects, including sagging energy, poor physical performance, headaches and nausea.
It's important to note that when you're calculating your carb count you are focusing on net carbs. "Net" carbs are the ones that affect your blood sugar. You can calculate a food's net carb value by subtracting its grams of fiber from its total grams of carbohydrates.
What to Eat on Each Low-Carb Plan
All low-carb diets encourage you to avoid bread, pasta and sugary treats, which are high in carbohydrates. Low-carb diets tend to put a focus on eating more meat, poultry, fish, cheese, oils and leafy greens.
A moderate low-carb diet of 100 to 150 grams per day might include 1/2 cup of grains, such as brown rice or pearled barley, at two or three meals. According to the USDA, brown rice contains about 21 grams of net carbs per 1/2 cup serving. You could enjoy 1/4 to 1/2 cup of starchy vegetables, such as winter squash or carrots; one to two pieces of fresh fruit, such as one-half of an apple and a whole peach; and 1/4 cup of black or cannellini beans at meals, too. Moderate servings of healthy fats, such as an ounce of nuts or one-quarter of an avocado, are also allowed at most meals.
A very-low-carb diet, like the keto diet, has you subsist mostly on animal protein, fats and non-starchy vegetables. Even your vegetable intake at each meal is restricted to keep your carb intake extremely low. Coconut oil, fatty fish, olive oil and modest servings of cheese contribute most of your fat as these items are low in carbs. You might have eggs and bacon for breakfast; a cheese stick and almonds as a snack; a burger patty with cheese and an egg for lunch; and chicken and vegetables stir-fried in coconut oil for dinner.
Which Low-Carb Diet Is Right for You?
It may take some experimentation to determine which low-carb diet is right for you. If you're considerably overweight or obese and need to lose weight desperately, a very-low-carb, or ketogenic, diet might be right for you in the short-term. Usually, this diet yields pretty dramatic weight loss, but it isn't without risks and side effects, so you should consult with your doctor before starting. Harvard Health Publishing notes that extremely low-carb diets like keto are unlikely to be followed long-term due to the highly restrictive nature of the diet.
When you first start eating low-carb, a moderate low-carb diet may not feel too restrictive and still provides you with energy for exercise and enough carbs to ward off the unpleasant symptoms that can accompany extremely low-carb plans. Active individuals may find this moderate-carb reduction meal plan best supports their lifestyle and weight-loss goals, and provides adequate energy to fuel workouts.
Low-carb diets may not be the right fit if you have certain medical conditions or are pregnant or breastfeeding. Always consult with a registered dietitian or physician before starting a low-carb diet.
Pros and Cons of Going Low-Carb to Lose Weight
According to the Mayo Clinic, a low-carb diet is usually used for weight loss but some low-carb diets may have potential health benefits like reducing risk factors associated with type 2 diabetes and metabolic syndrome.
A low-carb diet may also be beneficial for lowering triglycerides and increasing protective HDL cholesterol, according to Harvard Health Publishing.
An older 20-year study of 82,802 women, published November 2006 in the New England Journal of Medicine, evaluated the relationship between heart disease and low-carb diets. Women who consumed low-carb diets high in vegetable sources of protein and fat had a 30 percent lower risk of heart disease when compared to women who consumed a diet lower in fat and higher in carbohydrates. While a significant improvement was shown, the women who at low-carb diets high in animal protein and fat did not see the same benefit.
The takeaway with low-carb diet benefits may be in the overall quality of the diet and not necessarily the carbohydrate count.
The Mayo Clinic warns if you suddenly cut carbs you may experience a variety of temporary health effects, including:
- Bad breath
- Muscle cramps
- Skin rash
- Constipation or diarrhea
It's also possible that vitamin and mineral deficiencies can take hold when following a low-carb diet long term. These vitamin and mineral deficiencies can increase the risk of bone loss and cause gastrointestinal disturbances. Also, because low-carb diets may be lacking in key nutrients, these diets are not recommended for children or teens, as their growing bodies need the nutrients from fruits, vegetables and whole grains.
It's not entirely clear what long-term health risks a low-carb diet may cause, as most research studies have lasted less than a year, according to the Mayo Clinic.
Read more: 5 Possible Risks of a Keto Diet
- Mayo Clinic: "Low-carb diet: Can it help you lose weight?"
- Harvard Health: "Low-Carbohydrate Diets"
- New England Journal of Medicine: "Low-carbohydrate-diet score and the risk of coronary heart disease in women."
- Dietary Guideline for Americans: "DIETARY GUIDELINES FOR AMERICANS 2015-2020 "
- Harvard Health: "Ketogenic diet: Is the ultimate low-carb diet good for you?"
- USDA: "Rice, brown, medium-grain, cooked"