Atkins 20® Low Carb Diet Facts

Understanding the Atkins 20 Diet in full is important before beginning. Find out how many carbs you can eat on a low carb diet & more.

Q: What is the Atkins Diet?

The Atkins Diet® is the original leading low-carb weight loss plan that provides quick, effective, satisfying and balanced weight loss based on an extensive body of scientific research. The Atkins Diet is designed to “flip the body’s metabolic switch” from burning carbs to burning fat. Graduated carb introduction limits blood sugar and insulin spikes, which cause hunger and cravings, and result in overeating and weight gain.


Atkins has the additional application of being the weight loss plan of choice for the millions of people who have a reduced ability to process carbohydrates – those who have varying levels of “carbohydrate intolerance.”


The Atkins 20 plan consists of four phases, with gradual increased carb intake for each phase. The plan allows an individual to find his or her perfect carbohydrate balance that is ideal for their personal weight loss or maintenance. Atkins dieters are motivated to change and maintain their eating patterns with delicious and healthy food options.

Q: How can individuals following Atkins ensure they are getting a fully balanced, nutritional diet?

The Atkins Diet includes a wide variety of foods throughout the entire plan and encourages the consumption of a healthy balance of nutrient dense food, adequate protein, a full array of high-fiber vegetables, low glycemic fruits and healthy fats. It teaches every individual to discover their own perfect carbohydrate balance.

From Day 1 of the Atkins Diet, the concentration is on adequate intake of protein and fat, and a wide variety of nutrient-dense vegetables to supercharge the body’s fat burning power and jumpstart weight loss. This recommended amount of daily vegetable intake is even higher than what is recommended by the USDA.

Progressing through the Atkins 20 Diet, seeds, nuts, legumes, low glycemic fruits, and eventually whole grains are gradually added back in, with the amount dependent on each individual’s personal carbohydrate tolerance.

Q: How long can I stay on Phase 1 of Atkins 20?

The longer you consume no more than 20 grams of carbs daily, the more body fat you will burn. We recommend staying in this phase no later than when you are 15 pounds from your goal weight.


Depending on how much weight you need to lose, you can safely continue with Phase 1 as long as the following three conditions are met:


  • Your blood chemistry, lipid values, blood pressure or blood sugar levels continue to improve or remain stable and within normal limits. (You will have to visit your doctor to have these levels tested.)
  • You feel well and are experiencing a high energy level, normal sleep patterns and stable moods.
  • You are not bored. Boredom could lead to cheating and undermine your efforts.

However, it is important to understand the entire Atkins Nutritional Approach. The ultimate goal of the program is to advance from the Phase 1/through Phase 2 and Phase 3, culminating in Phase 4 or Lifetime Maintenance, which should become your permanent way of eating. By following these steps, you can find your own personal carbohydrate balance that maintains your new weight and prevents weight gain. Moving from one phase to another will help you maintain a healthful weight, feel good and decrease your risk factors for chronic diseases such as heart disease, hypertension, and diabetes.


That being said, if you have a great deal of weight to lose, you can certainly stay on Induction for six months or even longer. When you switch to Phase 2, your rate of loss will naturally diminish. On the other hand, if you have a modest weight loss goal, say 20-30 pounds, and lose the first pounds rapidly, you may want to follow the Atkins 40 plan so you can establish the good eating habits that will become part of your ongoing lifestyle and end yo-yo dieting.

Q: How do I know when to move through the phases of Atkins 20?

You have two options of when to move past Phase 1.


The first option is to move to Phase 2 after just a few weeks. Your carb intake will increase to 25g net carbs per day, and you will reintroduce nuts and seeds. As you continue to lose weight, you will increase to 30g net carbs per day and reintroduce dairy, such as Greek Yogurt, fresh cheeses, and milk. From there, you’ll add back legumes, and vegetable juice.


The balancing process enables you to find what works for you. Understanding your personal carb tolerance is the bridge from a weight-loss diet to a diet for life. This process can involve some fits and starts as you increase the variety of foods, but it’s essential to understanding your unique metabolism.


  • Pros: More variety in what you can eat; more options for moving past a plateau because you can always return to a lower level of carb intake; easier segue to a sustainable way of eating.
  • Cons: Slightly slower weight loss; more food choices may be too tempting or confusing.

Your second option is to remain in Phase 1 for more than 2 weeks. Continue to consume 20 grams of Net Carbs a day beyond the first two weeks. Try adding nuts and seeds to your list of acceptable foods. Nuts are full of protein and healthy fats and are relatively low in Net Carbs, thanks to their high fiber content.


To make it easy, swap out 3 grams of Net Carbs from other foods for 3 grams of nuts or seeds, but without letting your intake of foundation veggies dip below 12 grams of Net Carbs. You’ll still have 5 grams for Atkins bars and shakes, sweeteners, dressings, or condiments.


Move to Phase 2 no later than when you’re within 15 pounds of your goal weight. At that point it’s time to start transitioning to a permanent way of eating by introducing foods higher up the Carb Ladder.


  • Pros: speedier weight loss, greater structure, and fewer choices, meaning fewer opportunities for temptation
  • Cons: boredom; no options for moving past a plateau without reducing Net Carbs below the recommended level, which can be extremely frustrating and demotivating.

Q: In addition to weight loss, what are some of the health benefits associated with the Atkins Diet?

Independent third-party clinical research has found that the Atkins Diet reduces risk factors for heart-disease, insulin resistance and diabetes.


Additionally, the average American consumes nearly 130 pounds of added sweeteners each year, according to the U.S. Department of Agriculture (USDA…). By eating carbohydrates in moderation, the Atkins Diet helps individuals (even those without diabetes) maintain stable blood sugar levels, leading to fewer carb cravings and more energy, among other health benefits. Scientific research has consistently found that subjects at a high risk for Coronary Artery Disease (CAD) that were following the low-carb approach had improvements in their cholesterol profiles, decreasing their risk of developing CAD.


There are also many digestive benefits that come with following Atkins. Fiber requirements can be easily met because the Atkins Diet replaces highly refined, low-fiber carbohydrates with salad greens, fresh vegetables, low sugar fruit, nuts, seeds and whole grains. The diet includes lots of vegetables to replace processed foods, which increases fiber intake. A high-fiber diet is the best way to lower risk factors associated with the colon. Additionally, numerous scientific studies have confirmed that those eating a high-fiber diet have lower cholesterol levels and fewer incidences of heart disease than those on a low-fiber diet.

Q: Can vegetarians or vegans follow the Atkins Diet?

The Atkins Diet allows individuals to consume a wide variety of foods, all framed within a context of eating fewer carbohydrates and sugars. The diet can be followed as a vegetarian or vegan. Vegetarians can start in Phase 2 of Atkins 20 at 30 grams of Net Carbs and introduce seeds and nuts before berries. Vegetarians will can get their protein from eggs, cheese and soy products. Vegans can get sufficient protein from seeds, nuts, soy products, soy and rice cheeses, seitan, legumes and high protein grains like quinoa. Vegans can start in Phase 2 of Atkins 20 at 50 grams of Net Carbs so they can have nuts, seeds and legumes from the start.

Q: It is common knowledge that Atkins limits carb intake, but does the diet allow for individuals to eat any carbs?

The Atkins Diet is a low-carb, not a no-carb plan. People frequently mistake Phase 1 of Atkins 20, for the entire Atkins plan. During Phase 1, the plan allows dieters to eat 20 grams of net carbohydrates (carbohydrates that impact one’s blood sugar level, calculated by: total grams of carbs minus fiber) daily, with 12 – 15g net carbohydrates coming from a full array of colorful, nutrient-dense vegetables. After the Phase 1 is complete, the carbohydrate count is gradually increased until each individual reaches his or her personal carb balance and goal weight. Atkins dieters can even enjoy whole grains and pasta in later phases if their personal carb tolerance allows.

Q: Isn’t Atkins criticized for having too much fat?

Atkins does focus on fat, but a balance of fats that are commonly agreed to be healthy, such as naturally occurring saturated fats found in animal protein, polyunsaturated fats found in vegetable oils, and monounsaturated fats like olive oil and avocado. If they wish, individuals can easily avoid almost all saturated fats while on Atkins by following the plan as a vegetarian.


It is important to remember that if carbohydrate levels are low, fat intake needs to be higher. When the body is in fat-burning (aka ketosis), it uses fat from our food intake and body fat for fuel. As you increase your carb level, the amount of fat consumed will decrease, and protein levels remain constant throughout the diet.


Research from more than 80 peer-reviewed independent studies has consistently demonstrated the diet’s safety and efficacy.

Q: Is it dangerous to lose weight very quickly?

When you start the Induction phase of Atkins, you may experience rapid weight loss for the first time in your life. Don’t worry. What makes the initial drop dramatic is that you lose a good bit of water weight in the first 3 to 4 days. That’s because eating fewer grams of carbohydrate results in fewer spikes in blood sugar, resulting in less insulin output. Insulin makes the body retain sodium, which, as you probably know, makes your body retain water. When you’re not producing as much insulin, this cycle slows and the effect is like taking a diuretic. After four days or so, however, you will also begin to lose body fat. Young men and people who have a lot of weight to lose are more likely to lose weight more rapidly at the start of the Atkins program.


Losing weight too fast is an issue only if:


1) You’re not eating enough, which could make you lose lean muscle mass. To lose only body fat, be sure to eat regular meals and take in adequate calories. If you aren’t hungry at meal times, have a small snack with your supplements. Also, drink at least 64 ounces of water every day.


2) You feel sick, weak, dizzy or fatigued. If you lose too fast, especially at the beginning of the program, you may be experiencing an extreme diuretic effect. This could deplete you of water and also some electrolytes, which contain sodium, potassium, calcium and magnesium. Signs of electrolyte depletion are muscle cramps and heaviness in your legs when climbing steps. You may need to add more vegetables to your meals to slow down weight loss and add a mineral supplement to replace lost minerals.


But if you feel well and aren’t starving yourself, you’re probably not losing too quickly. If you have just a few pounds to lose, you might slow the pace so that you can continue to learn good eating habits before progressing through the phases to Lifetime Maintenance. Simply move to Phase 2 and increase your daily intake of carbohydrates by 5 grams. If you are within five to 10 pounds of your target weight, move into the Phase 3 and increase your intake gradually, in 10-gram increments, until weight loss slows to about a pound or two a month. However, if you still have a lot to lose and you feel full of energy, simply feel good that you are dropping pounds easily.

Q: If I’m following Atkins 20, and stay at 20 grams of Net Carbs a day, why can't I have some in the form of a slice of whole grain bread or even a peanut butter cup, which has 20 grams of carbs?

There are two reasons this approach won’t work. For one, all carbohydrates are not created equal. The Atkins Nutritional Approach is designed to prevent blood sugar levels from spiking and causing the overproduction of insulin—a hormone that helps to convert carbohydrates to body fat. The first carbohydrates you need to add back to your diet when you move beyond Induction are more vegetables, then seeds and nuts, then berries and then—if you are still losing—legumes and grains. Even bread made from 100 percent whole-wheat flour contains enough refined carbs to produce this insulin-raising, fat-storing effect in many people. Later, if your weight loss is progressing well and you have increased your daily carb intake, you may eat an occasional slice of whole grain bread. As for the 20-gram peanut butter cup, it contains a lot of sugar—not to mention artery-clogging hydrogenated fat and sugar is the worst kind of carbohydrate.


Secondly, the Atkins approach is not about rapid weight loss—it’s about learning to eat a variety of nutrient-dense carbohydrates for the rest of your life. These are foods that are packed with the most antioxidant vitamins and healthful phytochemicals relative to the amount of carbohydrates—so you’re getting the most bang for your carbohydrate buck. Once you’ve reached your goal weight and established your personal carb balance, most people can enjoy whole-grain bread, fruit and even the occasional plate of French fries. Unfortunately, that conventional peanut butter cup just doesn’t make the grade!


If you find you need more variety and have less than 40 pounds to lose, you may want to consider following Atkins 40. Click here for more information.

Q: What is “Carbohydrate Intolerance” and Metabolic Syndrome?

Atkins offers a scientifically proven plan that delivers increased weight loss and health marker improvements among those who have carb intolerance. The Atkins Diet reduces carbs to begin weight loss, and then directs the dieter to increase their healthy carb intake until they find their perfect carb balance – the level where their body can effectively metabolize carbs and maintain their weight long term. No other weight loss plan does this.


Only a doctor can make a medical diagnosis of carb intolerance, but there is a simple way to spot the first indicator: waist measurement. Fat deposited at the waist is a particularly unhealthy type of fat (visceral fat), and increased amounts of visceral fat can be indicative of carb intolerance. Women with waist sizes greater than 35 inches and men with waist size greater than 40 inches should consider speaking with their doctors about carb intolerance. It is important to note that this is a simple guideline and health risks can vary with height and body type.

Q: Are nuts and seeds okay in Phase 1 of Atkins 20 even though they have carbohydrates?

Atkins is not about eating no carbs. It is about controlling carb intake and eating those that are most nutrient-dense. Different nuts and seeds have different percentages of fat, protein and carbohydrate. We don’t recommend eating them during the first two weeks of Induction. But after that if you are continuing to lose steadily, you can try introducing some.To make it easy, swap out 3 grams of Net Carbs from other foods for 3 grams of nuts or seeds, but without letting your intake of foundation veggies dip below 12 grams of Net Carbs. You’ll still have 5 grams for Atkins bars and shakes, sweeteners, dressings, or condiments.


However, it is worth mentioning that nuts are notoriously hard to eat in moderation. One leads to another until you may have eaten several ounces. Try buying the one- or two-ounce packets so you won’t be tempted to over indulge.

Q: I'm used to counting calories. How many am I allowed on the Atkins Diet?

The Atkins Nutritional Approach counts grams of carbohydrates instead of calories. In Phase 1, you are allowed 20 grams of Net Carbs. When you progress to Phase 2, you gradually add carbohydrates in 5-gram increments as you move toward Phase 3, and finally, in 10-gram increments as you approach Phase 4 the Lifetime Maintenance phase. On the Atkins Nutritional Approach we don’t make you count calories. However for weight loss purposes we suggest you shoot for a healthy range. For women that range is approximately 1500 to 1800 calories. For men that range is approximately 1800 to 2200 calories per day. Be sure to limit empty calories and follow the acceptable foods list for whichever phase you are currently in.


Research has shown that on a controlled carbohydrate program, more calories are burned than on a low-fat, high-carbohydrate diet, so there is a certain metabolic advantage to the controlled carb approach. But understand that this does not give you a license to gorge.


The real goal of the Atkins program is to learn eating habits that will enable you to permanently maintain a healthy weight and lifestyle. This includes changing old habits such as overeating that contributed to your original weight problem.

Q: I lost weight for the first few months, but now the scale just won't budge. How do I get off this plateau?

First, before you assume there is a problem, ask yourself some questions: Are you feeling better? Are your clothes fitting better? (You may be losing inches, not pounds, because muscle is more dense than fat.) Are you still losing, but at a slower rate? You may just need to continue a bit longer, making slight modifications. These include:

  • If you are in phase 2 you can try decreasing the number of grams of carbohydrate you are consuming by 5 or 10 grams.
  • Increasing the amount of fat and decrease protein if you are consuming more than 4 to 6 ounces per serving.
  • Finding and eliminating “hidden” carbs in the form of processed foods that may contain sugar.
  • Increasing your activity level.
  • Drinking at least eight 8-ounce glasses of water daily.
  • Cutting back on artificial sweeteners, cheese or excess protein.

Q: How is the Atkins Diet beneficial to those who have been diagnosed with type 2 diabetes?

Yes, a type 2 diabetic can overcome high blood sugar using Atkins since the diet helps regulate blood sugar. Protein, fat, and low-carb vegetables have the least effect on blood sugar, which means they will not cause very high blood sugar. However, if an individual is on blood sugar lowering medications, they need to work closely with their doctor to adjust medication dosage. The need for medication diminishes dramatically and quickly while on Atkins.

Q: What is carb creep and how can I avoid it?

When you start adding back carbohydrates as you move from Phase 1 into the progressively less restrictive phases of Atkins, some people begin to lose track of how many grams of Net Carbs they’re eating. If that happens, you are likely to regain the pounds you’ve lost. That is why it is very important to increase your daily carb intake by only five grams each week and to introduce only one new food at a time. That way, you’ll also immediately notice if a new food is causing you to experience cravings that lead to over-eating. Another way to stay in control is to keep a food diary so you can spot troublesome foods before they set up a pattern of cravings and gorging. For example, if you find after eating nuts, you are hungry again in a few hours, cut out the nuts and see if the hunger disappears.

Q: Once I've reached my goal weight, what kinds of foods are allowed and not allowed on Lifetime Maintenance?

Please note that on the Atkins diet you can eat some of the best foods on earth. See the Acceptable Foods Lists to find out more. Your personal maintenance regimen will be regulated by your carbohydrate threshold, which in turn is a result of your metabolism and your activity level. Younger people and men tend to have higher metabolisms than older people and women. If you have a high carbohydrate threshold and do some kind of physical activity/exercise on a regular basis, you may be able to regularly eat starchy vegetables, beans and other legumes, whole grains and fruit in moderation. On the other hand, if you have a low-carb threshold and are not very active, you may have to limit some of these foods. In either case, your nutrition program will continue to stress whole foods and avoid sugar, white flour, hydrogenated fats and many processed foods.

Q: What is the highest level of carbohydrate consumption per day recommended for Lifetime Maintenance?

The important concept to understand in order to maintain your weight is finding your personal carb balance. You should find the highest level that won’t allow you to regain weight or cause hunger and cravings. Each person has a personal carb balance, and a bit of trial and error may be required for you to find yours.

Q: Can I drink alcohol now that I am in Phase 2?

The body burns alcohol for fuel when alcohol is available. So when it is burning alcohol, your body will not burn fat. This does not stop weight loss; it simply postpones it. Since the alcohol does not get stored as glycogen, you immediately get back into lipolysis after the alcohol is used up. But keep in mind that alcohol consumption may increase yeast-related symptoms in some people and interfere with weight loss. If it does not slow your weight loss, an occasional glass of wine is acceptable once you are out of Induction so long as you count the carbohydrates in your daily tally. (A 3 1/2-ounce glass of wine contains about 4.3 grams of carbohydrate.) Spirits such as Scotch, rye, vodka and gin are acceptable, but do not mix with juice, tonic water or non-diet soda, all of which contain sugar. Seltzer, diet tonic and diet soda mixers are permitted. If you have added alcohol to your regimen and suddenly stop losing weight, discontinue your alcohol intake.

Q: I have been able to do Atkins successfully but now that I am in Phase 3, my appetite increased. Why and what can I do to manage it?

Appetite can return when you are no longer in lipolysis (fat burning). Or you may have added a food that may be causing your blood sugar to become unstable, contributing to hunger or the re-emergence of cravings. Examine what you’ve recently added and determine if it contains sugars or refined grain. Be sure that you are maintaining a regular intake of protein and fat and, if eating more of acceptable foods assuages your hunger, eat a bit more. If all else fails, stop the most recent additions until you get your appetite under control.

Q: What types of products and support does Atkins offer?

Atkins provides dieters with a wide variety of products, tools and support. The New Atkins for a New You and New Atkins Made Easy books provides readers with guidelines on how to follow the diet. A cookbook hit the stands in 2011 and is entitled The New Atkins for a New You Cookbook: 200 Simple and Delicious Low-Carb Recipes in 30 Minutes or Less.


Atkins also offers a variety of frozen meals, nutrition bars and shakes which can serve as a convenient meal, snack, or treat. Some of these products are indulgently sweet but low in carbs – so Atkins dieters can indulge their sweet tooth while managing hunger all day. They can be purchased at major retail stores or at Additionally, Atkins offers a free online community and resource center at with more than 1,600 recipes and menu plans, as well as shopping lists for each phase of the plan. Community Members get all the resources and support to complete the diet online for FREE at – other diets can cost upwards of $30 per month. Upon registration, a quick-start kit is available for FREE on to give dieters all the information they need to get started.

Q: How do Artificial Sweeteners Inhibit Weight Loss?

For many people artificial sweeteners can be a sensitivity that can cause slower weight loss or stop weight loss altogether. Everyone is different and may have different sensitivities. If you encounter a stall or plateau in weight loss, evaluate how much artificial sweetener you are consuming, and try reducing.

Q: Why do I need to avoid Nitrates/Nitrites?

Nitrates/Nitrites usually found in bacon, sausage and lunch meat, indicates that the item has been cured. These may have hidden carbs due to the ingredients used in the process. We recommend consuming meats that are clearly labeled “No Nitrates/Nitrites.” These hidden carbs may cause you to go over your daily intake which can stall weight loss.

Q: What is the most up to date Atkins Diet book?

The Atkins® 100 Eating Solution Easy, Low Carb Living for Everyday Wellness.  Our newest book by Colette Heimowitz dives into the Atkins 100 program, making it easy for anyone to stick to 100 net carbs a day while enjoying every meal and getting real results. With cutting-edge research and 50 delicious recipes, The Atkins 100 Eating Solution provides an exciting, mouthwatering variety of food, and also explains the Atkins 20 and 40 programs, including low carb cooking and eating out hacks. Whether you’re looking to lose weight, manage an illness through diet, or simply feel better in your body, The Atkins 100 Eating Solution is here to help.

Atkins: Eat Right, Not Less: Your Guidebook for Living a Low-Carb and Low-Sugar Lifestyle by Colette Heimowitz focuses on eating right—not less—for painless weight management and better overall health. Choose the program that works for you: Atkins’ classic approach (Atkins 20®), a better keto diet (Atkins 40®), or small changes that lead to big results (Atkins 100™).

Q: Where do I find Articles/Data regarding the Atkins Diet?

To find more information regarding articles or data supporting the Atkins Diet, please visit our SCIENCE and LIBRARY tabs. If you’re looking for information to share with your physician, please direct them to our Healthcare Professional Portal,