The aim of the Atkins diet is to lose weight by avoiding carbohydrates and controlling insulin levels. Dieters can eat as much fat and protein as they want.
Dr. Robert Atkins, an American cardiologist, created the Atkins diet in the early 1970s. It has evolved over time and now encourages people to eat more high-fiber vegetables and do more exercise.
This article is also part of a series called What are the nine most popular diets today?
Dr. Atkins was a cardiologist. He designed a diet that aimed to reduce carbohydrate intake significantly.
The Atkins Diet has four core principles.
These state that the dieter will:
- lose weight
- maintain weight loss
- achieve good health
- lay the permanent groundwork for disease prevention
According to Dr. Atkins, the main reason for putting on weight is the consumption of refined carbohydrates, especially sugar, high-fructose corn syrup, and flour.
How does it work?
When a person is on the Atkins Diet, their body's metabolism switches from burning glucose, or sugar, as fuel to burning its own stored body fat. This switching is called ketosis.
When glucose levels are low, insulin levels are also low. At this point, ketosis occurs. In other words, when glucose levels are low, the body switches to using its own stores of fat as a source of energy.
Before eating, a person's glucose levels are low, so insulin levels are also low. When a person eats, their glucose levels rise. This triggers insulin levels to rise.
The glycemic index is a scale that ranks carbohydrates on a scale from 0 to 100, based on how quickly they increase blood sugar levels after eating, and by how much.
Refined carbohydrates, such as white bread and candy, contain high levels of glucose. They are called high glycemic foods. The carbohydrates enter the blood rapidly, and they cause insulin levels to rise quickly.
Other types of carbohydrates, such as oats, do not affect blood glucose levels so quickly or so severely. They have a low glycemic load, and they appear lower down the glycemic index.
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 carbohydrates are those with a low glycemic load.
Using the fat in the body
If there is no glucose in the body, ketosis will occur. During ketosis, the body will transfer some of the fat stores in fat cells to the blood to be used as energy.
The Atkins diet works on the basis that a diet that is low in carbohydrates. This causes the body to burn more calories than it would on other diets, because it encourages ketosis.
Dr. Atkins suggested that a person´s saturated fat intake should be kept to a maximum of 20 percent of all the calories they consume.
For people with type 2 diabetes, or metabolic syndrome, the Atkins diet claims to lower, and sometimes eliminate, the need for medications.
However, diabetes specialists warn that although watching carbohydrate and glucose intake are a vital part of diabetes care, the Atkins diet is not a simple solution for diabetes.
The Atkins diet has four phases:
Phase 1: Induction
Calorie consumption from carbohydrates is limited to less than 20 grams (g) each day. Carbohydrates come mainly from salad and vegetables, which are low in starch. The dieter eats high-fat, high-protein food with low-carbohydrate vegetables, such as leafy greens.
Phase 2: Balancing
Nutrient-dense and fiber rich foods are added as additional sources of carbohydrates. These include nuts, low-carb vegetables and small amounts of fruit.
These are added gradually:
- 25 grams is added during the first week of phase 2
- 30 grams during the second week, and each subsequent week until the person stops losing weight
When the person stops losing weight, they reduce their daily intake of carbs by 5 g until they slowly start to lose weight again.
Phase 3: Fine-tuning, or pre-maintenance
Dieters increase their carbohydrate intake by 10 g each week until they begin to lose weight very slowly.
Phase 4: Lifetime maintenance
The dieter starts adding a wider range of carbohydrate sources, while carefully monitoring their weight to ensure it does not go up.
This version of the diet starts with 40 g of net carbs a day, instead of 20 g.
A person's sense of well-being must continue.
If the person's weight starts to go up, they should ease back on their daily carbohydrate intake and cut out any of the new carbohydrates they have been introducing.
Foods to eat include:
- meats, including beef, pork, and bacon
- fatty fish and seafood
- low-carb vegetables, such as kale, broccoli and asparagus
- full-fat dairy products
- nuts and seeds
- healthy fats, such as extra-virgin olive oil, coconut oil, and avocado oil
A day's menu might be:
- Breakfast: Cheese omelet with low-carb vegetables
- Lunch: Chicken salad with nuts
- Dinner: Meatballs with vegetables
Snacks might include leftovers, a hard-boiled egg, Greek yogurt, or nuts.
Foods to avoid
Dieters should avoid:
- sugar, such as soft drinks, cakes, and candy
- grains including wheat, spelt, and rice
- "diet" and "low-fat" foods, as they can be high in sugar
- legumes, such as lentils, beans, and chickpeas
During induction, high-carb fruits, such as bananas, apples, and grapes and high-carb vegetables, such as carrots, should be avoided.
The Atkins diet aims to help prevent health conditions, such as metabolic syndrome, diabetes, high blood pressure, and cardiovascular disease. However, losing weight on many diets can achieve this.
A person who continues with the Atkins diet will probably lose weight, but most people do not continue long-term.
Studies have found that most dieters are no longer following the program after 2 to 3 years.
However, more research is needed to confirm the benefit of the Atkins diet compared with other diets.
In the early phases, some people have reported adverse effects, including:
As restricting carbohydrates causes a person's body to use up fat rather than glucose for energy, a buildup of ketones can result. This can lead to nausea, headache, mental fatigue, and bad breath.
People who use diuretics, insulin, or oral diabetes drugs should not follow the Atkins diet. It is not suitable for people with kidney disease. Pregnant or breast-feeding women should not engage in this diet.
Anyone who is considering a radical change to their diet should talk to a doctor first.