Low-Carb Diets

An Overview of a Low-Carb Diet

You've probably heard that following a low-carb diet can help you lose weight, control blood sugar, or become healthier in other ways. If you are new to this idea, you may wonder just what a low-carb diet is, whether it works, and how to go about making this change to the way you eat.

What Is a Low-Carb Diet? Three Approaches

"Low-carb diet" is a broad term encompassing many popular diet books (think Atkins and South Beach Diets), as well as eating plans that don't follow a rigid format, but advise limiting the consumption of foods that are high in carbohydrate and/or are especially glycemic (raise blood sugar).

Low-carb diets may also be referred to as reduced-carbohydrate or low-glycemic diets.

When you read about low-carbohydrate diets, "low-carb" is defined in many different ways, from slightly less carbohydrate than is generally recommended all the way down to very low amounts of carbohydrate per day. That said, there are three general approaches to a lower-carb way of eating:

1. Just Reduce Carbohydrate: Basically, the thinking is that any reduction in carbohydrate is helpful because increasing numbers of us have exceeded the amount of carbohydrate our bodies can easily handle.

This approach is mainly focused on reducing or eliminating added sugars and other refined carbohydrates. The "No White Foods" strategy, which involves eliminating sugars (of all kinds), white flour, white rice, and potatoes from the diet, fits in this category.

You may want to start by cutting back on starchy and sugary foods and watch what happens.

Resource: 7 Easy Carb-Cutting Steps

2. Find the Best Amount of Carbohydrate for You: There is no doubt that each of us has a different degree of carbohydrate tolerance. We can think of this as a continuum: people who can eat sugar all day long with no ill effects all the way to diabetics with very poor blood glucose control.

As we age, our carbohydrate tolerance often erodes and we have a greater blood glucose response to carbohydrate, even if our blood glucose stays in the "normal" range. We may develop insulin resistance or creep closer to prediabetes; these are signs that there is probably damage to the beta-cells in the pancreas, which make insulin.

Approaches that seek to help people find the optimal carbohydrate level usually advise reducing carbohydrate to a fairly low level and then gradually adding carbohydrate until there are adverse effects such as:

  • Weight loss ceases
  • Weight gain occurs
  • Carb cravings return
  • Blood glucose control diminishes
  • Blood triglycerides rise
  • Other negative symptoms return (poor concentration, low energy level, high blood pressure, etc.)

When one of these negative things start to happen, the advice is to cut the amount of carbohydrate back down a bit. Examples of this type of approach are the Atkins and South Beach Diets.

Resource: How Much Carbohydrate Is Right for You?

3. Seek a Ketogenic Diet: A ketogenic diet is a very low-carb diet that causes the body to primarily use fat for energy rather than glucose.

This puts the body into a state sometimes called "keto-adaptation" or "fat adaptation." This state has some metabolic advantages, such as improved stamina. One type of ketogenic diet is used to treat epilepsy, and ketogenic diets are under investigation to treat other health issues. Although there is some individual variation, a diet moderate in protein and below 60 grams of net carbohydrate per day is ketogenic in most people. Some can eat as much as 100 grams per day and remain in ketosis, while others must stay near 20 grams.

Resource: What Is a Ketogenic Diet?

Isn't the Atkins Diet a Fad Diet?

There have been numerous medical studies about low-carb diets. Many of these studies use Atkins or other popular low-carb plans as the basis of the low-carb part of the research. So far, none of the dire predictions for bad health outcomes from following the Atkins Diet or other low-carb plans have come true, and this includes at least one study that followed people up to six years. 

When fad diets are placed head-to-head with low-calorie diets, low-carb diets almost always show more weight loss and greater improvement in health markers such as blood glucose, blood pressure, and blood lipids.


Are Low-Carb Diets Good for Everyone?

Probably everyone can benefit from not eating too much sugar. Major health organizations are now telling us to limit the added sugars we eat to several teaspoons per day (learn more about these recommendations, and how quickly added sugars in our diet can add up).

The extent to which people will benefit from greater carbohydrate reduction probably has to do with how well our individual bodies handle carbohydrate, as sugars and starches in our food all end up as sugars in our bodies. I think the science is clear that people with a related cluster of issues including insulin resistance, prediabetes, type 2 diabetes, and metabolic syndrome are more likely to benefit from low-carb diets than from other dietary approaches. (It's worth pointing out that most people with these conditions do not know it.) This also includes people with so-called normal weight obesity.

People who don't have these issues probably have more leeway in their dietary approaches for weight loss and improved health.

While they, too, can benefit from carbohydrate reduction (insulin sensitive people do tend to lose weight on a low-carb diet), they are more likely to respond to other healthy eating approaches as well.


What Would I Eat on a Low-Carb Diet?

Mostly what you eat on a low-carb diet is lots of non-starchy vegetables; meats and/or eggs, and other sources of proteinlow-sugar fruits (such as berries); dairy foods (such as cheese and yogurt); nuts and seeds; and foods with healthy fats. Note, also, that it is absolutely possible to follow a low-carb vegetarian diet.

There are also some nice "extras" available, such as low-carb tortillas and low-carb condiments. You might be surprised at the wide variety of meals that can be put together with low-carb ingredients, even including baked goods and desserts.


Is a Low-Carb Diet Nutritious?

You may say: But I thought it was bad to cut out a food group. That certainly can be problematic if you're not careful about what you do eat. But a low-carb diet can certainly fulfill all of your nutrient requirements if you choose foods wisely.

Resources: Making Your Carbs Count

How Do I Get Started on a Low-Carb Diet?

If you want to try the simple method of just cutting back on carbs to see what happens, try following the aforementioned 7 Easy Carb-Cutting Steps. As you do, keep these 6 Simple Low-Carb Food Rules in mind. 

That said, many of us—perhaps even most of us—can benefit from a more structured approach. In this case, it will help to inform yourself and do some planning. The following resources can help:

How Much Should I Eat on a Low-Carb Diet?

There is no set amount of food to eat when following a low-carb way of eating. Once you are eating the right amount of carbohydrate for you, your appetite should reset and you won't be as hungry. You should eat when you're hungry and eat until you are satisfied on foods that are allowed on the version of low-carb eating that you select.

Are There Problems to Be Aware Of?

Yes, there are common mistakes that can be easily avoided, and common problems that are usually easily remedied. For example, some people buy into the many myths and misconceptions about low-carb diets and think they need to just eat meat all day long, which leads them to hate the diet, feel bad, not be properly nourished, and become constipated.  

Also, anyone taking medications to lower blood glucose or blood pressure should check with their doctor before starting a low-carb way of eating, as dosages will often need to be adjusted.


A Word From Verywell

Once your body adapts to your new way of eating, you may find you get many rewards. Many people find, for example, that heartburn is less or even gone. You may find that you are able to concentrate better and have more energy. As with any diet approach, knowledge is power. Make this change from an place of education to get the best results and stay well.



Accurso A, Bernstein RK, et al. Dietary carbohydrate restriction in type 2 diabetes mellitus and metabolic syndrome: time for a critical appraisal. Nutrition and Metabolism (Lond). (2008) Apr 8;5:9

Cornier MA, Donahoo WT, et al. Insulin sensitivity determines the effectiveness of dietary macronutrient composition on weight loss in obese women. Obesity Research Apr 13(4) (2005) 703-9.

McClain AD, Otten JJ, et. al. Adherence to a low-fat vs. low-carbohydrate diet differs by insulin resistance status. Diabetes, Obesity, and Metabolism. Jan;15(1) (2013) 87-90

Shai, Iris, et al. "Weight Loss with a Low-Carbohydrate, Mediterranean, or Low-Fat Diet." The New England Journal of Medicine. 359:229-241 (July 17, 2008)

Volek, JS, Phinney, SD. Carbohydrate restriction has a more favorable impact on the metabolic syndrome than a low fat diet. Lipids. Apr;44(4) (2009) 297-309.

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