What Is the Atkins Diet?

Atkins diet

Verywell / Debbie Burkhoff

The Atkins diet is probably the most widely recognized low-carb diet plan. The Atkins diet has gone through significant changes since it was first introduced in the 1960s by Robert Atkins, M.D., a cardiologist. The current program allows you to choose from different eating styles based on your weight loss or health goals. Atkins 20 and Atkins 40 are described as keto diets by the company. Ketogenic diets limit carbohydrate intake so that your body burns fat as fuel.

Weight loss is likely to occur on the Atkins plan, especially during the program's more restrictive phases. According to the company, an average person can expect to lose 1–2 pounds per week on the plan. Some people who are already at a healthy body size might use the Atkins program to maintain their weight or boost health.

The 2021 U.S. News and World Report Best Diets ranks the Atkins diet number 33 in Best Diets Overall and gives it an overall score of 2.1/5.

What Experts Say

The Atkins diet is a carbohydrate limiting weight loss diet. Health professionals agree limiting fiber-rich food groups can lead to constipation and nutrient imbalances. A focus on counting carbohydrates prompts eating by numbers instead of exploring individual likes and needs.
—Willow Jarosh, MS, RD

What Can You Eat?

The Atkins diet plan relies on knowing how much carbohydrate is in everything you eat. Specifically, consumers count their net carbs. Net carbs are calculated by checking the total grams of carbohydrates in your portion of food and subtracting the grams of fiber and sugar alcohols or glycerin (if applicable).

There are three Atkins programs based on different levels of net carb intake per day. The company recommends that you check with your healthcare provider for personalized advice before choosing a program to manage a medical condition.

What You Need to Know

Over the years, Dr. Atkins refined his approach as new research about diet and nutrition became available. The Atkins diet still focuses on limiting carbohydrates but offers consumers different intake levels for consumers based on their health goals. They are also advised to make nutritious food choices, including healthy fats, fiber-rich carbohydrates, and a wide range of protein sources such as seafood, beef, and poultry.

People think of the Atkins diet as primarily a weight loss diet, but some people also use the eating program to control blood glucose, reduce blood pressure, or gain other health benefits.

One of the diet's main goals is to help each find the optimal amount of carbohydrates for that person's body

Atkins 20

The Atkins 20 plan is what most would consider being the classic Atkins plan. It is designed for those who have over 40 pounds to lose, have a waist size of over 35 (for women) or 40 (for men), are pre-diabetic, or diabetic.

People on this program start by consuming just 20 net carbs per day. They eat various approved (foundational) vegetables, lean meat, cheese, and healthy fats to meet their energy needs. After two weeks on Atkins 20, people on this plan can begin to add fiber-rich carb sources in five net carb increments. Then gradually, they learn to incorporate more healthy carbohydrate choices to reach and maintain their goal weight.

There are four phases to the Atkins 20 program:

  • Induction Phase: For two weeks or longer, consumers keep their net carbs at the lowest level.
  • Balancing Phase: People on the program slowly add grams of net carbs to find the best carbohydrate balance.
  • Fine Tuning Phase: Clients are advised to make small tweaks to reach and maintain their goal weight for at least a month.
  • Lifetime Maintenance: You continue to eat a healthy diet with limited carbohydrates to maintain your goal weight.

Atkins 40

This plan offers a more relaxed program where dieters eat from all food groups from day one. The plan is designed for people who have 40 pounds or less to lose, those who prefer a wider variety of food choices, or for women who are breastfeeding and intending to lose weight.

Atkins 100

This is the most relaxed Atkins eating program. It is designed for those who want to maintain their current weight, who prefer the widest variety of food choices, or for women who are breastfeeding and have a goal to maintain weight. The company also suggests this program for those who are pregnant as long as they have approval from their healthcare provider.

You consume about 100 grams of net carb per day with no foods that are off-limits on this plan.

On each of the Atkins plans, net carbs are to be divided between three meals and two snacks per day, so that blood sugar remains stable throughout the day. You don't count calories on these programs, but portion size recommendations are provided. Additionally, it is recommended that certain foods (such as added fats) are limited.

What to Eat
  • Non starchy vegetables

    High fiber fruits

    Fish and shellfish



    Cheese (limited)

    Nuts and seeds


What Not to Eat
  • Starchy vegetables (induction only)

    Processed meats

    Sugar-sweetened beverages


    Trans fat

    Vegetable oils

    Higher carb fruits (induction only)

    Legumes (induction only)


Fruits, Vegetables, and Legumes

Non-starchy vegetables are encouraged on the Atkins eating plan. On the most restrictive phase of Atkins 20 (Phase 1), consumers are advised to consume 12–15 grams of net carbs from foundational vegetables per day.

In this program, you start the first phase of the plan by consuming 40 grams of net carbs per day from vegetables, fruits, nuts, legumes, and whole grains. As dieters approach their goal weight, they add carbs in 10 net carb increments to find their personal carb "sweet spot" to maintain their healthy weight.

Starting with Phase 2 on Atkins 20 and Atkins 40 and Atkins 100, fruits are included in the plan. You can also add legumes.

Meat and Cheese

Meat is not required on the Atkins plan. If you prefer not to eat meat at all, you can follow the vegetarian program. But if you follow the traditional plan, many types of protein are encouraged. Cheese is also on the acceptable foods list, but Atkins recommends consuming no more than 3–4 ounces per day. Processed meats with nitrates are not recommended.

Nuts and Seeds

After two weeks on Atkins 20, people on this plan can begin to add berries, nuts, and other fiber-rich carb sources in five net carb increments.

Pros and Cons

  • No calorie counting

  • Tailored to goals

  • Multiple plans

  • Weight loss

  • Hard to adjust

  • Carbohydrate counting

  • Expensive

Choosing the less restrictive Atkins plans may offer a less complicated and effective way to lose weight. An April 2020 review of diets for weight loss and blood pressure reduction showed that the Atkins diet produced an average of 12 pounds of weight loss, the highest in the study.

If you currently consume a standard American diet, adjusting to an Atkins plan may be challenging, especially if you choose to go on the Atkins 20 plan.

Additionally, even though you don't have to count calories on the Atkins diet, you need to count carbs, calculate net carbs, and balance carbs between meals and snacks. You'll also need to use food lists to make sure you're consuming compliant foods. For many busy people, this work may seem overwhelming. As an alternative, consumers can choose to purchase an Atkins meal plan and get pre-packaged meals, smoothies, and snacks.

The Atkins diet requires plenty of protein sources and limits cheaper, processed foods. For this reason, it might be more expensive than your usual diet.

Sample Shopping List

The foods you will need to buy for the Atkins diet depend on which phase or version of your plan. Fruit is introduced in Phase 2 on Atkins 20 and is consumed on Atkins 40 and Atkins 100. You may wish to visit a butcher as you will need 4 to 6 ounces of protein at each meal. Vegetarians can use alternative protein sources. Keep in mind that this is not a definitive shopping list and if following the diet, you may find other foods that work best for you.

  • Non-starchy vegetables (spinach, arugula, kale, bell peppers, eggplant)
  • High fiber fruit (berries, honeydew, and cantaloupe)
  • Fish and shellfish
  • Poultry
  • Beef
  • Eggs
  • Atkins brand bars, shakes, snacks
  • Cheese
  • Olive oil
  • Butter

Is the Atkins Diet a Healthy Choice for You?

While the Atkins diet was a novel approach to weight loss when it was first introduced, there have been quite a few similar diets established in the years since Dr. Atkins' book was first published in 1972.

The Atkins diet's macronutrient balance varies substantially from guidelines provided by the U.S. Departments of Agriculture and Health and Human Services. The 2020-2025 Dietary Guidelines for Americans suggest that an adult who consumes a 2,000 calorie per day diet should consume 130 grams of carbohydrates per day.

On the Atkins diet, you consume fewer than 50 grams of carbohydrates per day. Carb intake varies on the plan you choose, and clients can tailor their carb intake to meet their health goals on the Atkins 100 plan. But you can expect to consume substantially more fat, slightly more protein, and fewer carbs than recommended by the USDA.

Low carb eating has become one of the most common approaches to weight loss, wellness, and weight maintenance. However, the program still differs substantially from USDA recommendations.

Health Benefits

Increase Healthy Food Intake

If you replace those less healthy foods with more nutritious foods (such as those on the Atkins Acceptable Foods lists), you will likely increase your important micro and macronutrient intake.


Protein and fat are digested slowly and have a high satisfaction rate. The Atkins diet may keep you more satisfied with your meals than other weight loss diets for this reason.

Reduce Processed and Refined Foods

For many people, restricting carbohydrates means eliminating heavily processed, high-sugar, high-starch foods which contribute calories without substantial nutrition.

Health Risks

Side Effects

Typically, people consume most of their calories from carbohydrates. Cutting back on carbs can lead to symptoms including headaches, fatigue, mood swings, and constipation.

Short Term Weight Loss

The fast weight loss effects you might experience on the Atkins diet could be short-lived. Much of the initial weight loss will likely be due to water loss from limited carbohydrates. Regaining weight can be frustrating and demotivating for many people.

A Word From Verywell

While the Atkins diet has gained acceptance from many in the nutrition and health communities, some are still worried that the diet is too restrictive to maintain for the long term. Additionally, high saturated fat intake is still a concern—with some studies indicating no relationship to heart health and others still showing a negative effect.

If you choose to try the Atkins diet, speak with your health care provider and talk about how your carbohydrates and fat intake might change on the plan. Based on your health history and current status, your medical provider can make personalized suggestions about whether the program is likely to be healthy for you and modifications that you might make to make the diet more manageable.

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Article Sources
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  1. Anton SD, Hida A, Heekin K, et al. Effects of Popular Diets without Specific Calorie Targets on Weight Loss Outcomes: Systematic Review of Findings from Clinical Trials. Nutrients. 2017;9(8):822. Published 2017 Jul 31. doi:10.3390/nu9080822

  2. Shilpa J, Mohan V. Ketogenic diets: Boon or bane? Indian J Med Res. 2018;148(3):251–253. doi:10.4103/ijmr.IJMR_1666_18

  3. U.S. Department of Health and Human Services and U.S. Department of Agriculture. 2020 – 2025 Dietary Guidelines for Americans. 9th Edition. December 2020.

Additional Reading
  • Westman E, et al. A New Atkins for a New You. Touchstone Press. New York, New York. 2010.