The SlimFast diet is a commercial calorie limiting eating plan which first appeared in the late 1970s. The diet was at first a shake only plan but later incorporated SlimFast bars. The current version was modified in the late 2000s and uses the 3-2-1 format standing for three SlimFast snacks two SlimFast meal replacements and a well-portioned dinner.
What is known today as the Nutrisystem diet began as a protein shake diet in the 1970s before morphing into its present format of a meal delivery service. Pioneered by businessman Henry Katz, the Nutrisystem diet plan is highly structured with an emphasis on food with a low-glycemic score.
The Jenny Craig diet is an intensive weight loss and behavior change program pioneered by weight loss specialist Jenny Craig in the 1980s. The program relies on consultants and pre-packaged meals to instigate rapid and long term weight loss and behavior change results. The Jenny Craig diet plan requires subscription and purchasing of meals either online or from designated locations.