Low carbohydrate diets became popular in the 1970’s with the introduction of the Atkins Diet.  Atkins is designed to decrease carbohydrates – such as grains, starchy vegetables and fruits – and increase dietary protein and fat to aid in weight loss. The theory behind a low carbohydrate diet is to switch the body’s metabolism from metabolizing glucose (sugar) as energy to metabolizing stored body fat as energy. This process is called Ketosis. Ketosis begins when insulin levels are low which occurs when blood glucose (blood sugar) levels are low.

By reducing insulin levels it induces the breakdown of fat into ketone bodies and protein into keto acid.   It was thought that by inducing the breakdown of fat you would burn more calories. However, this thought was quickly refuted as research showed an overall decrease in calories caused such weight loss.

The question is:  Should you be consuming a Low Carbohydrate Diet? 
There are certain body systems that can only use carbohydrates as fuel.  The brain and the central nervous system are such systems.  Neither of these systems can use fat as an energy source. However, after 3-4 days without carbohydrates both the brain and central nervous system are forced to find alternative energy sources.  This alternative energy source is ketone bodies. Even though these systems prefer glucose as its fuel source, ketone bodies actually provide more energy than glucose due to the metabolic effects of ketones.

Low Carbohydrate Diet and Weight Loss

There is strong supportive evidence that following a low carbohydrate diet aids in weight loss.  However, there are contrasting theories regarding how an individual loses that weight.  One theory is that by consuming a low carbohydrate diet one decreases overall calories due to the increased satiety effect of protein.  Another theory is that there are in fact metabolic advantages of a higher protein consumption in combination with a low carbohydrate diet that results in weight loss.

Obesity Crisis

Low Carbohydrate Diet and Exercise

First of all, the average human body requires 60-65 grams of glucose per day.  The theory behind following a low carbohydrate diet (30- 50 grams of carbohydrates per day) in conjunction with exercising is that your body will always be in the “fat burning zone.”  By constantly being in the “fat burning zone” it is thought that the weight loss potential of your workout is greater.  However, there are no real conclusions that say this is what actually happens nor is it safe.  In reality, having an absence of glycogen in your muscles from following a low carbohydrate diet makes is harder for you to perform as well as before, thereby increasing risk of injury.  Nevertheless, following a version of a low carbohydrate diet is something that bodybuilders and fitness athletes use to maximize fat loss.  

Research shows that following a short-term low carbohydrate diet can maintain strength and fitness level and may be used when weight classes are involved.  However, it is not good for long term exercisers as ability to increase muscle mass, and  aerobic capacity is decreased as well as reduction in non-exercise physical activity.

Low Carbohydrate Diet and Diseases

Not only has low carbohydrate diets been used as a tool for weight loss but they have also been used to treat diseases.  The Ketogenic Diet, which is a low-carbohydrate diet, has been used since the 1920’s to treat epilepsy (seizures).  More recently, research in small studies have shown that the Ketogenic Diet has been successful in helping to reduce risks for:  heart disease, certain cancers, diabetes, acne, polycystic ovarian syndrome, and the metabolic syndrome. Thereby, if individuals can change the way individuals eat through nutritional interventions (food as medicine) it can reduce reliance on pharmaceutical treatments which could decrease the $750 billion annual cost of pharmaceuticals.


Before you go out and decide to start living a low carbohydrate lifestyle, it is encouraged to talk to your doctor. Risks involved in consuming a low carbohydrate diet include: headache, dizziness, weakness, fatigue, constipation, nutritional deficiencies, diarrhea and nausea. Another controversial risk involved in a low carbohydrate diet is the high intake of protein.  Some research indicates that a high protein diet in healthy individuals may cause kidney damage due to high levels of nitrogen excretion during protein metabolism. However, these studies are not conclusive and thereby  more research needs to be done.