What to Expect on the Atkins Diet

The traditional Atkins diet, called Atkins 20, has four phases. You can expect to cut back on your carbohydrate intake on each phase, but the most restrictive phase is the first one, called Induction. On later phases—or if you choose Atkins 40 or Atkins 100—your carbohydrate intake will be higher but still much lower than the intake recommended by the U.S. Department of Agriculture (USDA).

Regardless of which phase or which version of the plan you follow, you should expect to plan meals around protein and fat foods to decrease your intake of carbohydrates and stay within the limits suggested by the plan.

What to Eat

There is a separate list of acceptable foods for each phase of Atkins 20. You'll find Acceptable Foods lists on the Atkins website for Atkins 40 and Atkins 100.

The chart below outlines food recommendations for the first phase (Induction) of Atkins 20. Keep in mind that many of these foods are considered acceptable (in limited amounts) on Atkins 40.

On Atkins 100, there are no foods that are considered off limits. However, you can expect to keep your carbohydrate intake below 50 grams per day even on Atkins 100, so you'll need to keep portions of carbohydrate-rich foods small in order to maintain that goal.

Compliant Foods

Foundational Vegetables

The bulk of the carbohydrates in the Atkins diet comes from foundational vegetables. It's important to know the carbohydrate counts of the vegetables you are eating. People on Atkins should try to consume 12–15 grams of net carbs per day of vegetables like spinach, mushrooms, zucchini, cucumber, broccoli, asparagus, and tomatoes.

Fish and Shellfish

Those on Atkins are advised to consume a 4–6 ounce serving of fish. Breaded fish is off limits because of the carbohydrate count. But other types of fish and shellfish are advised including salmon, tuna, sardines, halibut, cod, or flounder.

Shellfish such as lobster, shrimp, and clams are acceptable foods. Oysters and mussels are OK on this phase, but since they are higher in carbs it is advised that you limit intake to four ounces or less.

Poultry

Atkins advises that you divide your protein intake between three meals and get it from a variety of different sources. Fowl including turkey, chicken, duck, pheasant, and goose are all acceptable. A recommended serving is 4–6 ounces.

Meat

Atkins clients are advised to consume meat in the recommended serving size (4–6 ounces) Acceptable types of meat include beef, lamb, pork, veal, and venison.

On the program, you do need to be cautious about certain types of meat including bacon, ham, and and other processed meats. These products may contain added sugars because they are cured with sugar. Atkins clients are also advised to avoid meats cold cuts and other meats with nitrates.

Eggs, Cheese, Cream

Eggs are a recommended source of protein on Atkins. Cheese contains some carbohydrate, so those on the program are advised to consume no more than 3–ounces per day. Some other dairy products such as cream, and sour cream can be consumed but goat’s milk, yogurt, cottage cheese, and ricotta is not advised.

Fats and Oils

While there is a popular myth that people on Atkins eat large amounts of butter and other added fats, this is not true. Atkins followers are advised to keep their added fat intake to 2–4 tablespoons per day. Acceptable fats include butter, mayonnaise, olive oil, walnut, and sesame oil.

Non-Compliant Foods

Grains and Grain Products

The standard American diet includes a wide range of foods made from grains. These foods are not to be consumed if you are on the first phase of Atkins 20. These foods include bread, pasta, cereal, muffins, bagels, other baked goods. You also wouldn't consume grains like rice, oats, or barley.

As you progress on Atkins, you'll learn to include limited grains in your diet. It is recommended that you choose whole grains that are high in fiber.

Fruit and Fruit Juice

While fruit and fruit juice provides several important vitamins, these foods and beverages also provide fructose and other sugars, making them high in carbohydrate. Some low-carb fruits can be added into your diet in later phases of Atkins, you'll avoid them completely on the first phase of Atkins 20.

Beans and Lentils

Beans and lentils (such as kidney beans, split peas, or garbanzo beans) are a good source of nutrients and protein. However, because these foods are also a good source of carbohydrate, you'll avoid them on most phases of Atkins 20.

Alcoholic Beverages

On the first phase of Atkins 20, you'll avoid alcoholic beverages completely. Beginning with phase 2 you can begin to enjoy these beverages in moderation and with caution. Clear liquors tend to have fewer carbohydrates, but mixers tend to be made with sugar.

Sugary Beverages

Most non-alcoholic flavored beverages are made with sugar or artificial sweeteners. Sugary beverages are off-limits. Beverages made with artificial sweeteners (Stevia, sucralose or saccharine) are allowed in moderation. It is advised that Atkins followers limit intake to the equivalent of three packets per day.

Nuts and Seeds

Nuts and seeds are another good source of fat and protein, but they also boost carbohydrate intake. In general, they are not advised on the induction phase of Atkins. However, if you have decided to stay in this phase longer than two weeks, you may swap out three grams of net carbs from vegetables for three grams of nuts or seeds.

Sauces, Condiments, Salad Dressing

While many sauces and salad dressing are made with fat, many also include added sugars. For example, ketchup and barbecue sauce are sometimes high in sugar. Salad dressings can also be a source of added sugar. These products are usually off-limits unless they contain no natural or added sugar.

Convenience Food

Most convenience or packaged foods, such as crackers, chips, boxed macaroni, and some frozen foods such as frozen pizza and French fries are to be avoided on the Atkins plan. These types of foods are often processed and full of carbohydrates and sugar.

Recommended Timing

Atkins is structured according to the amount of weight you have to lose and according to your goals for adopting the eating plan. The plan that you choose and your progress will determine the timing of the program.

Phase one (induction) on Atkins 20 should last two weeks. People can continue longer if they desire, as long as they tolerate the change well, or if they have a lot of weight to lose. During this time you limit your carb intake to 20 grams a day to get your body into ketosis. Phase 2, the balancing phase lasts until you are within 10 pounds of your goal weight.

During Phase 3, you'll fine-tune your diet and add slightly more food choices to your daily meal plan. You'll stay on this phase until you have been at your goal weight for at least one month. The last phase is known as Lifetime Maintenance. It is designed to be your eating plan for life.

Atkins 40 is for those who have less than 40 pounds to lose, are pregnant or breastfeeding, or those who prefer a wider variety of food choices. If you are pregnant or breastfeeding, physician guidance is needed. On this program, it is advised that you eat three meals per day and consume about 10 grams of net carbohydrates at each meal. You'll also consume two snacks each day that contain about five grams of net carbs each.

Atkins 100 is designed for those who want to maintain their weight. The program is designed to be a lifelong eating style. On this program, you consume three meals per day each containing about 25 grams of net carb each. Two snacks can also be consumed, each containing 10 to 15 grams of net carbs. It's important to note, however, that more studies need to be conducted regarding the efficacy of following a low carbohydrate eating plan for the long term.

Resources and Tips

There is a wealth of information available for free on the Atkins website. Those who are interested in the diet may also purchase any of the Atkins books. The most current book, "Eat Right, Not Less" was written by Colette Heimowitz, MS, and was published in 2017.

Those who prefer more convenience can choose to sign up for a paid plan or an Atkins meal kit. The meal kits include other resources and tools (such as a carb counter and shopping lists) to help you stick to the plan. There are also a number of free meal plans available for download on the website, in addition to other free resources including the latest low-carb research, clinical guidelines for following the diet, and a mobile weight loss tracker.

If you learn to cook low-carb compliant foods at home, you may be more successful on the plan. Most consumers can't afford to stay on a meal plan indefinitely, so if you plan to stick to Atkins for life, it is helpful to learn the skills needed to maintain the eating style early on. There is a substantial library of recipes on the website. You'll also find many Atkins-friendly recipes online.

Adjusting to Ketosis

For those following Atkins 20, it is also helpful to be prepared for side effects that you may experience during induction. When the body is not given carbohydrate to convert into energy for bodily functions, it will use (primarily) fat for fuel. The switch to a different source of energy will affect your body.

People experiencing ketosis due to the Atkins diet or any other low-carb diet may experience mood swings, constipation, bad breath (due to extra ketones expelled from the lungs), headaches, nausea, fatigue, kidney stones, or high levels of calcium excretion. To prevent these and other side effects, drink water frequently, don't skip meals, and stay relatively active. Contact your healthcare provider if symptoms are prolonged.

On Atkins 40 and Atkins 100, you are also likely to experience some symptoms from decreasing your carbohydrate intake. You may experience fatigue and constipation. Drinking enough water can help to ease these symptoms.

Modifications

People who are interested in Atkins but don't eat meat can choose to follow the Eco Atkins diet. The program, developed by researchers at St. Michael’s Hospital in Toronto, has a similar ratio of protein and carbs as the original Atkins diet but replaces high-fat animal protein with vegetable protein. This diet is recommended for vegans and vegetarians.

Customers who follow a gluten-free diet will find options at Atkins. In addition to providing gluten-free recipes, Atkins also offers several gluten-free products. According to the company, the products are not certified gluten-free by any third-party organization, but they do meet the requirements set by the FDA.

There are also many other low-carb diets that don't cut carbs quite as far as Atkins induction. They also lead to weight loss and the health benefits low-carb diets can offer. One approach may be to start out following all the rules of induction but be prepared to loosen up if you find that you're on the verge of quitting altogether.

A Word From Verywell

While many people are successful using the Atkins diet, it's not for everyone. The induction phase of the Atkins diet is very restrictive in order to produce dietary ketosis. It requires strict attention to guidelines for what you can and can't eat. It is helpful to examine the food lists and think about whether or not you are willing to give up certain common foods in order to be successful.

If you can't stick with the plan, remember that there are many diets that can help you lose weight. Consider making small changes to improve your health or lose weight—such as eating more fruits and vegetables. You can also work with your health care provider or get a referral to a registered dietitian to come up with a customized plan to boost wellness, reach or maintain a healthy weight.