What Is the Atkins Diet?

Atkins diet

Verywell / Debbie Burkhoff

The Atkins diet is a 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, MD, 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 to 2 pounds per week on the plan. People who are already at a healthy body size might use the Atkins program to maintain their weight. 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 a 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 different intake levels based on consumers' health goals. People on the Atkins diet 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 each person's body.

On each of the Atkins plans, net carbs are 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, certain foods (such as added fats) are limited.

Atkins 20

The Atkins 20 plan is what most would consider 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), have pre-diabetes or diabetes.

People on this program start by consuming just 20 net carbs per day. They eat various approved vegetables, lean meats, 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 5 net carbs at a time. 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: Two weeks or longer, keep net carbs at the lowest level
  • Balancing Phase: Slowly add grams of net carbs to find the best carbohydrate balance
  • Fine-Tuning Phase: At least one month; make small tweaks to reach and maintain goal weight
  • Lifetime Maintenance: Continue to eat a healthy diet with limited carbohydrates to maintain 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 people who are breastfeeding and wish to lose weight.

Atkins 100

This is the most relaxed Atkins eating program, allowing 100 grams of net carbs per day with no other restrictions. It is designed for those who want to maintain their current weight, who prefer the widest variety of food choices, or for people who are breastfeeding and have a goal to maintain weight.

What to Eat
  • Non-starchy vegetables

  • High-fiber fruits

  • Fish and shellfish

  • Poultry

  • Eggs

  • Cheese (limited)

  • Nuts and seeds

  • Beef

What Not to Eat
  • Starchy vegetables (induction only)

  • Higher carb fruits (induction only)

  • Legumes (induction only)

  • Grains

  • Processed meats

  • Sugar-sweetened beverages

  • Candy

  • Trans fat

  • Vegetable oils

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 to 15 grams of net carbs from these vegetables per day. On Atkins 20, you can add fruits and legumes starting with Phase 2. The Atkins 40 and Atkins 100 plans allow fruits and legumes at all times.

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 to 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

Pros
  • No calorie counting

  • Tailored to goals

  • Multiple plans

  • Weight loss

Cons
  • 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 at 6 months, the Atkins diet produced an average of 12 pounds of weight loss, the highest in the study. However, at 12 months, weight loss diminished in all diets, including Atkins. Researchers concluded that "at 12 months the effects on weight reduction and improvements in cardiovascular risk factors largely disappear."

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.

Even if you don't buy pre-packaged Atkins foods, the 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. 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, Brussels sprouts, cauliflower)
  • High fiber fruit (berries, pears, kiwifruit, oranges)
  • Fish and shellfish
  • Poultry
  • Beef
  • Eggs
  • Atkins brand bars, shakes, snacks
  • Cheese
  • Olive oil
  • Butter

Sample Meal Plan

Here are one-day sample meal plans for the Atkins 20, 40, and 100. This is not an all-inclusive meal plan and if following the diet, you may find other meals that work best for you.

Atkins 20

  • Breakfast: 5 ounces ground pork, 1 tablespoon avocado oil, 1/2 cup chopped red bell pepper, 1/4 cup chopped green onion, 1/2 cup shredded monetary jack cheese
  • Snack: Atkins vanilla shake
  • Lunch: Atkins frozen sesame chicken stir-fry
  • Snack: 3/4 cup sliced cucumber, 2 Tbsp. vinaigrette
  • Dinner: 6 ounces haddock fillet, 2 cups steamed broccoli florets, 1 tablespoon butter, 1/2 an avocado, 2 tablespoon vinaigrette

Atkins 40

  • Breakfast: 2 eggs scrambled with avocado, green onions and grape tomatoes
  • Snack: Atkins Peanut Butter Protein Wafer Crisp Bar, and half a granny smith apple
  • Lunch: 6 ounces cooked chicken breast, 1 ounce swiss cheese 1/2 small tomato, 1 dill pickle, 2 romaine lettuce leaves
  • Snack: Half a granny smith apple, 2 tablespoons almond butter
  • Dinner: Atkins Frozen Mexican-Style Chicken and Vegetables, 2 cups of steamed cauliflower rice, 1 tablespoon butter

Atkins 100

  • Breakfast: Atkins Dark Chocolate Royale Shake blended with 3/4 cup frozen riced cauliflower 1/2 cup raspberries
  • Snack: 1/2 medium sweet potato, baked and sliced 1/4 cup sour cream 1 tablespoon chopped green onions
  • Lunch: A wrap made from 4 ounces poached chicken breast, 2 tablespoon Italian Dressing, 1/2 medium cucumber, 1 whole wheat tortilla, 1/2 cup steamed cubed sweet potato
  • Snack: Atkins Birthday Cake Bar
  • Dinner: Chicken cacciatore served over 2 cups of spaghetti squash.

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 (USDA) 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.

Lastly, if you are watching your sodium intake, you may want to be careful about the foods that you choose. Frozen meals (any brand) can be higher in sodium. Read labels carefully to make sure that the meals you choose align with your nutritional and health goals.

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

Since weight loss can improve many health outcomes, the Atkins diet may confer benefits by successfully helping people lose weight. It may also offer other helpful side effects.

Increases Nutritious Food Intake

Followers of the Atkins diet are likely to replace those less healthy foods with more nutrient-dense ones, such as those on the Atkins Acceptable Foods lists. That means a likely increase in intake of important micronutrients (vitamins and minerals) and macronutrients (protein and fiber).

Satiety

Protein and fat are digested slowly and have a high satiety rate. The Atkins diet may keep you more satisfied with your meals than other weight-loss diets, which in turn could lead to better compliance.

Health Risks

For many people, an Atkins diet is a major departure from their typical eating pattern. That can mean some discomfort, as well as difficulty sticking with the program.

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 might make the diet more manageable.

Remember, following a long-term or short-term diet may not be necessary for you and many diets out there simply don’t work, especially long-term. While we do not endorse fad diet trends or unsustainable weight loss methods, we present the facts so you can make an informed decision that works best for your nutritional needs, genetic blueprint, budget, and goals.

If your goal is weight loss, remember that losing weight isn’t necessarily the same as being your healthiest self, and there are many other ways to pursue health. Exercise, sleep, and other lifestyle factors also play a major role in your overall health. The best diet is always the one that is balanced and fits your lifestyle.

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4 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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