Low carbohydrate diets aren’t new. They have been around for for decades. The Atkins Diet was introduced in 1972 but, even before that, bodybuilders were using low carbohydrate diets to get ripped before competitions.
Since the Atkins Diet is the most common low-carb diet, we’ll start with that. Essentially, the Atkins Diet is done through a series of phases. The first phase is the weight loss phase and is used to get the body into ketosis, a state in which the body burns fat for energy rather than glucose (blood sugar). During the first phase of the Atkins Diet, you restrict your intake of carbohydrates to 20 grams a day, eat a lot of high-protein, high-fat foods, and take dietary supplements. Once you’ve lost the bulk of the weight you intend to lose, you go to phase two and begin adding more carbohydrates and more variety to your diet. Eventually, you get to a maintenance phase where you simply eat a balanced diet every day and maintain your weight loss.
Many other diets have followed since Atkins’. In 2003, the South Beach Diet was introduced. This is a modified version of the Atkins Diet and allows for more vegetables and dairy.
The key to low-carb diets is the “glycemic index”. This is a term that diabetics know and understand as they continually work to keep their blood sugar levels stable. Carbohydrates directly affect blood sugar levels because carbohydrates are quickly broken down into blood sugar. Foods with a high glycemic index are most quickly broken down and cause blood sugar levels to spike and then drop. For example: orange juice has a high glycemic index and most diabetics avoid it if possible. Foods with a low glycemic index don’t cause blood sugar to spike and keep blood sugar levels steady. Ideally, we all want to have steady blood sugar levels.
High-fiber grains, fibrous vegetables and some fruits are ranked fairly low on the glycemic index. Fat has a glycemic index of 0 because it has no effect on blood sugar. (Thus high-fat foods are often included in low-carb diets.) Research has shown that diets that are made up of mainly low-glycemic foods help to lower cardiovascular risk factors like high cholesterol and pre-diabetes.
Low-carb diets like Atkins and South Beach, while they start with just meat, fat and vegetables, always lead the dieter to another phase where they really need to consider the glycemic index and eventually incorporate whole grain carbs (which are low on the glycemic index) rather than allowing the dieter to go back to refined and high glycemic carbs.