What Are Low-Carb, High-Fat Diets? Are They Healthy? |US News


What does a low-carb, high-fat diet look like – and is it a healthy way to eat?

(Getty Images)

There’s scientific evidence that this eating approach could help you lose weight and shield you from some chronic diseases. There’s also research that suggests a low-carb, high-fat eating regimen can lower your defenses against some chronic conditions and – in the short term – create unpleasant side effects.

To learn what the research and experts say, read on:

What Is a Low-Carb, High-Fat Diet?

There’s no single definition of a low-carb, high-fat eating regimen, says Bethany M. Doerfler, a clinical research dietitian in the division of gastroenterology and hepatology at Northwestern Medicine in Chicago. She works in her division’s Digestive Health Center. While there are some well-known eating plans that are low-carb and high-fat – like the keto diet – you need not follow one of those regimens to adhere to this style of eating. You can craft your own low-carb, high-fat eating plan with a registered dietitian. This sort of regimen deviates from the Institute of Medicine’s acceptable macronutrient distribution range, which recommends adults in the U.S. get 45% to 65% of their daily calories from carbs, 20% to 35% from dietary fat and 10% to 35% from protein.

While individual low-carb, high-fat eating regimens vary, they typically call for obtaining less than 50% of your daily calories from carbohydrates, Doerfler says. Fat intake ranges from between 30% to 40% of daily caloric intake, and protein consumption might land in the 10% to 30% daily range. If you plan on trying a low-carb, high-fat eating regimen, Doerfler recommends consulting a registered dietitian first. He or she can help you develop an eating plan that provides the nutrition you need and can help you attain your health goals.

Can It Be Healthy?

A low-carb, high-fat eating approach can be healthy – provided the food choices are smart, says Tasha Temple, a registered dietitian with Northside Hospital in Gwinnett, Georgia. Making healthy choices can reduce the risk of developing chronic diseases like heart disease, diabetes and metabolic syndrome, which includes obesity, she says.

Research suggests that a low-carb, high-fat diet can help you lose weight, which in turn can help ward off chronic conditions like diabetes and heart disease. For example, a meta-analysis of 11 randomized controlled trials involving 1,369 participants suggests that people experience a greater decrease in body weight while adhering to a low-carb, high-fat plan (compared to other eating regimens), according to a study published in the European Journal of Nutrition in March 2018.

Adhering to a low-carb, high-fat eating regimen may increase the number of calories your body burns, research published in November 2018 in the BMJ, a weekly, peer-reviewed medical journal, found. The study involved 164 participants with obesity who had lost up to 14% of their weight during the initial phase of the study while adhering to a weight-loss diet. During the 20-week maintenance phase, the participants were provided different amounts of carbs in their diets. Some received 60% of their daily calories from carbs, while others consumed 40% and members of a third group derived 20% of their daily calories from carbs. The amount of energy expended by the people consuming 20% of their daily calories from carbs was significantly greater than the energy burned by those on the high-carb regimen, researchers found.

Risks and Side Effects

There are risks associated with a low-carb, high-fat eating regimen, research and some experts suggest:

  • Nutrient deficiency, according to a Harvard Health Letter published in October 2018.
  • Liver problems caused by increased fat intake.
  • Constipation.
  • Increased risk of bad cholesterol, according to the 2018 study in the European of Journal Nutrition.

A separate study suggests that a low-carb, high-fat diet may put you at risk for some chronic diseases. Generally, “most natural carbohydrate-rich food sources are high in dietary fibers and micronutrients,” according to research published in the European Journal of Nutrition in June 2018. Diets that call for consumption of less than 30% carbohydrates run “a realistic risk of low fiber and micronutrient intake,” the study says. Various meta-analyses suggest that consuming the proper amount of fiber is associated with a significant reduction in the risk for Type 2 diabetes and cardiovascular disease, the study says. Consuming a diet that’s low in fiber is associated with constipation. Consuming sufficient amounts of dietary fiber may also be helpful in supporting weight management, research suggests.

Some people who embark on a low-carb, high-fat diet might experience temporary side effects like weakness or fatigue, muscle cramps, skin rash, bad breath, headaches, constipation or diarrhea, says Lisa Jones, a registered dietitian based in Philadelphia. “However, these side effects should subside as the body adjusts to the new eating regimen,” Jones says.

Healthy Eating Choices

While the risks of consuming a low-carb, high-fat diet are genuine, such a regimen can be healthy if you make the right food choices, Temple says.

Specifically, consuming proteins that include lean meats, chicken and fish, non-starchy vegetables and healthy fats that are low in saturated fats could comprise a healthy eating regimen, she says. You should also stay away from highly processed offerings, says Tammy Ward, a registered dietitian with UC Health, the health system affiliate to the University of Cincinnati. Highly processed foods include bacon, cold cuts, snack foods like chips, cookies, pies and cupcakes. Conventionally, these foods also contain more carbs than recommended on low-carb diets. If you want to indulge your sweet tooth and prefer healthy options, there are many recipes online utilizing whole food ingredients, such as almond and/or coconut flour, cocoa powder and nut butters for creating new low-carb “sweet” treats, Ward says. The primary higher-carb foods to avoid or strictly limit are grains, starchy vegetables and sugars.

  • Meats (other than bacon, sausage and hot dogs).
  • Chicken.
  • Fish.
  • Nuts.
  • Seeds.
  • Avocados.
  • Peanut butter.
  • Nut butters.
  • Eggs.
  • Olive oil.
  • Olives.
  • Legumes (in limited quantities).
  • Dark, leafy salads.
  • Non-starchy vegetables, such as spinach, Brussels sprouts, broccoli, cauliflower and cabbage.

Getting Enough Fiber

It’s important to keep in mind that some low-carb, high-fat diets don’t distinguish between highly refined, processed carbs from offerings like candy, cookies and potato chips and high-quality carbohydrates that come from much healthier sources such as legumes, whole grains and fruits, says Lisa Garcia, a registered dietitian based in Laconia, New Hampshire.

Dietary fiber is also important in maintaining regular bowel movements. High-fiber foods add a feeling of fullness, which is essential to losing pounds or maintaining a healthy weight. Insufficient fiber could lead to constipation.

To make sure you get enough fiber, Garcia recommends consuming some foods that would be prohibited or limited under some low-carb regimens, like legumes.

Adding non-starchy vegetables to meals and snacks would also help you meet your daily fiber requirements, Jones says. “It’s a best practice to make half of your plate vegetables when trying to meet your daily fiber requirement,” Jones says. “This goal can be accomplished by adding non-starchy vegetables to meal and snack choices throughout the day.”


Please enter your comment!
Please enter your name here