Loading... Please wait...


Sign up to our newsletter and receive the latest stories, product news and special offers.

O2 Diet

Diet Origins

Keri Glassman, MS, RD, CSN, created this diet plan which is based upon the Oxygen Radical Absorbsance Capacity (ORAC) scale originally developed by the USDA.  Glassman is a nutrition contributor for CBS's The Early Show and also is a contributing editor at Women's Health magazine.  

Diet Philosophy 

When cells die, oxygen molecules known as free radicals are released and create health related problems such as premature aging, heart disease, cancer, poor immune function, and other health problems.  Although free radicals are normal in the body, they can build up and cause health problems.  Antioxidants can offer protection from excess free radicals.  These are primarily found in plants and in healthy fats, although small amounts are found in fish, eggs, and dairy products.  The ORAC scale is a measure of the oxygen radical absorption capacity in foods.  The USDA recommends eating a minimum of 3,000 to 5,000 ORAC points a day for optimum health.  The diet author argues that you should eat as much as possible without overconsuming calories.  The O2 Diet is built around consuming a minimum of 30,000 ORAC points per day.

Diet Claims

This diet claims to have many benefits:

  • Improved memory and cognition
  • Prevent cancer
  • Reverse heart disease
  • Lower stress
  • Protect joints
  • Glowing skin
  • More energy
  • Mental focus
  • Improved sex life

Diet Structure  

The goal of the diet is to eat at least foods containing 30,000 ORAC points per day which can result in a 10 percent to 25 percent increase in the antioxidant power of your blood.  This plan has an initial 4 day period where the minimum ORAC value is 50,000.  The diet author argues that excess ORAC Value points are not toxic and their is no ill effect as long as you are not overconsuming calories and not avoiding other foods that are nutritionally beneficial in other ways unrelated to the ORAC Value scale.  Foods with minimal ORAC Values - starches and all meat, fish, milk, and yogurt - are still important components of a diet.   The diet promotes lean proteins, omega-3s, dairy products that are low in fat and sugar, monounsaturated and polyunsaturated fats as well as essential fatty acids (omega-3s).   Saturated fats are avoided but not totally banned such as those found in butter and meats.  The diet plan results in an almost equal parts carbs, fats and protein although carbs tend to be a little higher than fats and proteins. 

Banned Foods

This diet does not allow the following foods in the first month (longer if you can):

  • Trans fats (hydrogenated or partially hydrogenated)
  • White sugar
  • Artificial sweeteners 
  • Soft drinks
  • Processed meats (nitrates are the villain)
  • Fried foods
  • Sugar
  • Sodium

Eating Out

This diet plan does not restrict eating out because it is easy to follow the recommendations with appropriate food selection.


Desserts are allowed but they are considered "indulgences" to be used sparingly.  Some dessert foods, such as dark chocolate, rate very high on the ORAC points system and can contribute significantly to the daily ORAC value.  


Alcohol is allowed but most beverage do not have ORAC values and only contribute empty calories.  Alcoholic beverages with high ORAC Values include Sangria and red wine.  Drinks like vodka and club soda can contribute to ORAC values with the addition of lemon juice.     


A minimum of 45 minutes of cardio and 10 minutes of stretching are recommended per day.

Diet Testing

The diet author claims that eating a high-ORAC diet increases the anitioxidant power of human blood 10 to 25 percent.  "While researchers are still learning precisely how these foods work, they do know that foods high on the ORAC cale can help you lose weight, improve memory and cognition, prevent cancer, reverse heart disease, lower stress, and protect joints.  They minimize your skin's lines and intensify its glow."

"Researchers have just begun to scratch the surface of antioxidant research:  there are now literally hundreds of studies linking anti-oxidant-rich foods to better health, including everything from reduced heart disease to a decreased likelihood of cancer.  And while taking too many antioxidant supplements in pill form may be harmufl, there's absolutely no downside to consuming more nutrient-dense fruits and vegetables." 

"The majority of research, hundreds of well-respected studies, conducted at leading universities has shown that the most powerful foods are also among the most common.  In fact, the plain old apple in one of the best antioxidant foods around.  

Anticipated Weight Loss

The diet author expects that one will lose 2 to 3 pounds per week following this diet. 

Measuring Tools


Keeping a journal of sleep hours, exercise, pampering (food based facial masks), fluid intake, meal statistics (food, time, hunger status) is recommended.

ORAC Value

The ORAC scale is a measure of a food's abilityl to control disease causing free radicals.  The USDA has developed a list that ranks the ORAC values of 277 foods.  


This diet references the BMI as more meaningful than weight but that it too is just a small part of what is important.  What is your BMI?

Hunger Quotient

The hunger quotient is a scale from 1 (stuffed) through 10 (famished) The 02 diet author recommends that you should maintain between 6 (slightly hungry) and 4 (slightly satisfied) at all times.


7 to 8 hours a night is recommended


This diet does not address the use of supplements.

View Sample Diet Now