The Atkins diet promotes weight loss through a low-carbohydrate eating plan. Proponents of the Atkins diet say it can also prevent or improve many health conditions, including high blood pressure and heart disease. The diet aims to help a person lose weight by limiting carbohydrates and controlling insulin levels. Dieters can eat as much fat and protein as they want.
What is the Atkins Diet?
Cardiologist Robert Atkins created the Atkins diet in the 1960s, with the first book being published in 1972. According to Dr. Atkins, the main reason for weight gain is the consumption of refined carbohydrates, especially sugar, high fructose corn syrup, and flour. He believed that carbohydrates - not fat - were responsible for health problems and weight gain. As a result, his diet focused on eating plenty of fat, some protein and very few carbs.
The Atkins diet has evolved over time and now encourages people to eat more high-fiber vegetables and do more exercise than it did in the past. There are now two Atkins diets: Atkins 20 (the original diet, which is described here and is based on an intake of 20 grams of Net Carbs) and the new Atkins 40, which is less strict (based on an intake of 40 grams of Net Carbs).
The main features of the diet haven't changed:
- Lose weight and improve health by eating a low-carbohydrate diet.
- The diet consists of protein, vegetables, and healthy fats.
How the Atkins Diet Works
The goal of the Atkins diet is to change your metabolism. You burn stored body fat, rather than carbs, for energy. When a person follows the Atkins Diet, their body’s metabolism switches from burning glucose, or sugar, as fuel to burning stored body fat. This switch is called ketosis. When you don’t eat carbohydrates, your body turns to stored body fat, which the liver breaks down. This process creates ketones, which the body can then use for energy.
Read also: Understanding the Atkins Diet
Before a person eats, their glucose levels are low, so their insulin levels are also low. When that person eats, their glucose levels rise, and the body produces more insulin to help it use glucose.
Net Carbs and Glycemic Index
The Atkins diet doesn’t limit the amount of fat you can eat, and you won’t have to count calories or measure portion sizes. But you will have to count carbs carefully. The Atkins diet severely restricts carbs, especially in the early stages. It uses a tracking method called net carbs, which is the total number of carbs minus its fiber content in grams. Net carbs are the total carbs minus fiber and sugar alcohols. Sugar alcohols have a minimal effect on blood sugar levels. According to Dr. Atkins, the best carbs are those with a low glycemic load.
The glycemic index (GI) is a scale that ranks carbohydrates, or carbs, from 0 to 100, depending on how quickly they increase blood sugar levels after consumption, and by how much. Refined carbs, such as white bread and candy, contain high levels of glucose. These foods have high GI scores, as their carbs enter the blood rapidly, causing a glucose spike. Other types of carbs, such as beans, do not affect blood glucose levels so quickly or severely. They have a low glycemic load and score lower on the glycemic index.
Fruits and grains are high in carbs, and a person on the Atkins diet restricts these, especially in the early stages. However, these foods are also good sources of vitamins, minerals, fiber, and antioxidants. To make up for the lack of nutrient-rich foods, the Atkins diet encourages people to use vitamin and mineral supplements.
Phases of the Atkins Diet
There are four phases of the Atkins diet, starting with the most restrictive and gradually getting easier. Beginning at phase 1 promotes more weight loss. You can start the diet at a later stage, but you won’t lose as much weight.
Read also: Delicious Atkins Dinners
Phase 1: Induction
A person consumes less than 20 grams (g) of net carbs each day. This is the strictest part of the diet. You must avoid all fruit, bread, grains, starchy vegetables, dairy products (except cheese and butter), and alcohol. At this stage, carbs come mainly from salad and vegetables, which are low in starch. The dieter eats high fat, high protein food with low carb vegetables, such as leafy greens. That's significantly less than the FDA recommendation of 275 grams of carbohydrates daily. The goal of phase 1 is to produce fast weight loss and to rev up your body's ability to burn fat. And because you lose the most weight during this phase, it is designed to motivate you to stick with the diet.
Phase 2: Ongoing Weight Loss (Balancing the Diet)
This phase allows up to 30 net carbs. You still lose weight, although not as quickly as you did in phase 1. People gradually introduce nutrient-dense and fiber-rich foods as additional sources of carbs. These foods include nuts, seeds, low carb vegetables, and small amounts of berries. People can also add soft cheeses in this phase. During phase 2, you slowly add some whole food carbohydrates back to your diet, such as berries, legumes, nuts, tomato juice, and yogurt. You can eat between 25 and 50 Net Carbs daily.
In phase 2, a person adds:
- 20-25 g of carbs per day during the first week
- 30 g of carbs during the second week
- 30 g each subsequent week until weight loss slows to 1-2 pounds a week
The aim of phase 2 is to find out how many carbs an individual can eat while continuing to lose weight. This phase continues until the individual is within 5-10 pounds of their target weight.
Phase 3: Pre-Maintenance (Individualizing & Optimizing the Diet)
You can increase your net carbs by up to 10 grams per week. Continue this phase until you reach your target weight. Dieters increase their carbs intake by 10 g each week. Weight loss will now be slow. They can start introducing legumes, such as lentils and beans, fruit, starchy vegetables, and whole grains to the diet. During phase 3, you continue to add a variety of carbohydrates to your diet, including more fruits, starchy vegetables and whole grains. You can eat 50 to 80 Net Carbs daily.
Read also: Atkins Diet for Vegetarians
People continue in this phase until they reach their target weight and maintain it for a month. Phase 3 lasts for at least a month after reaching your desired weight.
Phase 4: Lifetime Maintenance
This is a maintenance phase, where you can eat up to 120 net carbs a day as long as you stay at your target weight. The dieter starts adding a wider range of carbs sources, while carefully monitoring their weight to ensure it does not go up. Net carb intake will vary between individuals, but it will usually be between 40-120 g a day. Once you reach your ideal weight, you continue to eat a predominantly low-carbohydrate (80-100 Net Carbs per day) diet for life. By this time, you should have a good idea of how many carbohydrates you can eat to maintain your weight.
Atkins 40
This version of the diet starts with 40 g of net carbs per day instead of 20 g. Each day, people consume 6-8 servings of vegetables, 3-4 servings of protein (4-6 ounces per serving), 3 times 1-tablespoon servings of added fat, and 3-5 servings of other carbs, with 5 net carbs in each serving. When the person is within 5-10 pounds of their target weight, they can add 10 g of net carbs each week. Once they reach their target weight, they can use the Atkins carb counter to help them keep on track.
What to Eat on the Atkins Diet
Depending on the phase, people may eat:
- Vegetables that are rich in fiber and nutrients, such as broccoli, salad greens, and asparagus
- Low sugar, high fiber fruit, for example, apples, citrus and berries
- Complex carbs, including legumes, and whole grains
- Plant fats such as nuts, avocado, olive oil and seeds
Sample Menu
A day’s menu might be:
- Breakfast: Cheese omelet with low carb vegetables
- Lunch: Chicken salad with nuts and a side of cherry tomatoes and cucumbers
- Dinner: Meatballs with at least 1 cup of vegetables, such as asparagus, cooked in fat
- Snacks: A hard boiled egg, Greek yogurt, or nuts.
Foods to Avoid or Restrict
Foods to avoid or restrict, depending on the phase of the diet, include:
- Starchy vegetables, such as corn and potatoes
- Fruits with high sugar content, such as pineapple, mango, papaya, and bananas
- Sweets, including cookies, candies, cakes, and soft drinks
- Refined or simple carbs, including white bread, pasta, and foods containing processed grains
During induction, some foods, such as carrots, apples, and legumes, are not suitable. In time, however, a person can reintroduce them.
Benefits of the Atkins Diet
The Atkins diet has been around for decades, and it has some benefits. This diet works for some people because it:
- Won’t make you hangry: Protein and fat suppress the appetite, which is an advantage for people who feel hungry on other diets.
- Cuts calories: If you’re restricting your carbs, you’re also cutting out many unhealthy foods that are common in the American diet. Think white bread, fried foods and sugar. Most American diets are 55% carbohydrates or higher. If you cut out all those carbs, you’ll probably eat fewer calories overall and lose weight.
- Controls blood sugars: Eating very few carbohydrates can help control blood sugar, especially in people who have diabetes.
Studies have shown that people who stick to a low-carbohydrate diet like Atkins can lose weight. A study in The Journal of the American Medical Association comparing diets found that women on the Atkins diet lost more weight and experienced more health benefits. After one year on the Atkins diet, people in the study lost an average of 10 pounds. They also had improved triglyceride levels and lower blood pressure. But experts say any diet that helps you lose weight will probably improve your cholesterol.
Authors of a 2017 review found evidence that the Atkins diet followed for 12 months can be more effective for weight loss than other popular diets. Another review found that people following the Atkins diet scored well on blood pressure, cholesterol levels, and weight loss, compared with people on the ZONE, Ornish, and LEARN diets.
Risks and Considerations
Although Atkins can help people lose weight, it has some drawbacks. The diet:
- Allows processed meats: Processed meats may raise the risk of heart problems and certain cancers. But because they are low carb and high fat, many people following Atkins eat a lot of them.
- Excludes healthy foods: Many people restrict fruits and some vegetables to stay under their carb limit. These foods contain important vitamins, minerals, disease-fighting phytochemicals and fiber. Eliminating food groups can cause nutrient deficiencies and health problems.
- Has side effects: Eating a very low-carb diet like Atkins can cause electrolyte imbalances, constipation, dangerously low blood sugar and kidney problems.
- Promotes processed foods: The Atkins diet sells and promotes bars, shakes and ready-made meals that help people stick with the plan. But many of these items contain artificial sweeteners, processed ingredients, high-saturated fat and sodium that won’t do your health any favors. A long list of ingredients isn’t a good sign.
- Has questionable long-term benefits: We don’t have evidence that this diet is good for you over the long term. All of the studies have looked at how it affects your health for less than a year or two.
According to an older 2006 study, people have reported the following adverse effects, especially in the early stages: headache, dizziness, nausea, weakness, fatigue, constipation, and unusual smelling breath. When the body uses fat rather than glucose for energy, ketones can build up before the body uses them efficiently for fuel. This process increases urinary excretion of electrolytes, which may contribute to these symptoms.
The 2006 study authors caution that a low carb diet may not be suitable for everyone, especially those with a risk of kidney disease, as it may make kidney stones more likely. They add that healthful carbs, such as whole grains, can be beneficial for people with diabetes. Atkins limits the intake of whole grains until the later phases of the diet. The study also describes the Atkins diet as unpalatable and difficult to follow in the long term.
Many experts caution that eating a diet high in saturated fats can increase your risk of heart disease and cancer. A high-protein diet can be harmful to those who have had previous kidney problems. And critics say the Atkins diet omits important nutrients such as vitamin C and potassium. People on the Atkins diet are encouraged to take an iron-free multivitamin and mineral supplement and an omega-3 supplement that contains fish oil.
Tips for Following the Atkins Diet
- Focus on healthy foods: Limit or avoid processed meats and other processed foods. Eat healthy fats, like those found in fish, nuts and olive oil. Include healthy carbs, like fresh fruits and whole grains, as part of a healthy, long-term eating plan.
- Consume plenty of protein
- Get carbs from vegetables
- Eat a snack, for example, a hard boiled egg, around an hour before exercising
- Eat a high protein meal within 30 minutes of finishing