Liquid Diets and Protein Shakes

Medical weight loss plans typically include a a liquid diet phase in which participants consume protein shakes in place of regular meals. These programs are designed to help moderately to severely obese patients achieve successful weight loss, and the liquid, or meal replacement stage is intended to initiate a period of rapid weight loss from which a patient can build a long-term weight loss and weight management plan.


Protein shakes and food replacement help control hunger while patients are experiencing a phase of rapid weight loss. This phase typically lasts a maximum of twelve weeks, while patients learn to control their eating behaviors. These products are intended to provide proper nourishment, while also carefully controlling food and calorie intake, allowing patients to stay free of regular food and compulsive, unhealthy eating habits.

Nutritional Information

The Kaiser Liquid Diet

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Protein shakes should be carefully regulated for the proper amount of protein, calories, fiber, and nutrients. The typical liquid diets phase consists of between 800 to 900 calories a day, with drinks that are evenly consumed over the course of the day. According to the Mayo Clinic, the average adult requires between 46 to 56 grams of protein per day. Shakes should also meet all daily nutritional requirements for vitamins, minerals, and fiber content.

Expected Results

A meal replacement phase for a medically supervised weight loss plan will often result in a weight loss of 3 to 4 pounds a week. Patients who complete a full 12-week phase can therefore expect a weight loss of 36 to 48 pounds if they fall within the cited weight loss statistic per week. This weight loss is often an extremely important source of motivation for weight loss patients who have struggled with diets in the past, and it has been shown that it may motivate patients to continue their weight loss in the subsequent phases of a program, when patients transition to a low-calorie, balanced diet.

Expert Insights

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Medical supervision of liquid diets and meal replacement programs is critical. These programs are not recommended for people who are only slightly overweight because they can result in a loss of muscle tone and a slowing of the body's metabolism. Patients should consult a medical specialist before beginning a plan to determine their individual calories needs and rule out any underlying health concerns. Close monitoring of patient health, with regular medical check-ins is highly advised during a liquid diet phase.