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Optifast vs. slim-fast

Updated July 19, 2017

Those wishing to shed pounds sometimes select liquid-based, meal-replacement type diets. Two of the diet industry's programs---Slim-Fast and Optifast---both offer shakes and bars. What's the difference between them?

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Slim-Fast is a program that combines shakes and bars for meal replacement with a meal plan that users can customise online.

The Optifast meal replacement plan is geared toward those who are more than 22.7 Kilogram overweight. The plan is also sometimes used to assist those preparing for gastric bypass surgery.


While both Slim-Fast and Optifast products can be purchased online, Slim-Fast also maintains a presence on supermarket shelves with its meal replacement shakes and bars.

In order to participate in Optifast, you must have a complete medical exam, where potential risk factors can be assessed. Those who are admitted to the program will receive a weight-loss plan that's based on goals and meal replacement.


Slim-Fast offers online support, such as its website's community forum. The site also offers recipes and meal plans.

Optifast clients are monitored throughout the process, during weekly individual and group sessions where users meet with doctors and nutritionists, who create meal plans that must be followed during the first two months back on food.


A notable difference between the Optifast and Slim-Fast programs is the cost, due to the level of support offered. Because the Optifast plan includes counselling and monitoring by health professionals, it is more expensive. To achieve some of the same benefits, those using the Slim-Fast plan may wish to visit a clinical nutritionist or invest time into researching healthy eating regimens.


Both Optifast and Slim-Fast claim their followers may experience weight loss and decreases in bad cholesterol, high blood pressure and high blood-sugar levels.

Many Slim-Fast users experience initial weight loss due to calorie restriction. As is the case with many diets, many followers don't maintain the loss once they go off the plan. Users must also remain aware of health problems that can occur due to calorie restriction and a loss of nutrients when choosing packaged, processed foods over whole foods.

Optifast users will likely lose weight initially on an all-liquid diet.

Always consult your physician before beginning any diet.

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