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What Is the Medifast Diet?

What Is the Medifast Diet?

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    The Medifast Diet was a meal delivery program that offers a variety of low-calorie diets through pre-packaged meals that are nutritionally fortified, low fat, and portion-controlled.

    The Medifast program aimed to help you hit your weight loss goals but is now part of the OPTAVIA diet program.

    How Does the Medifast Diet Work?

    After signing up to the Medifast community and selecting your program and support system, you receive a personalized weight loss plan and meal options to order each week. This plan is based on your physical attributes and weight loss goal. The theory behind these prepackaged meals is that by eating low-calorie, fat, and glycemic index foods, your body will start to burn fat for fuel.


    Progression from the five and one plan to the transition stage begins when the goal weight is reached. The duration of the transition phase is calculated by weight lost. Exercise is encouraged at all stages as it assists in weight loss and maintenance by burning calories.

    The Diet Plan

    The original and most studied Medifast diet is divided into three phases. The first is called Medifast 5 & 1 plan, which targets weight loss. Next, the transition phase focuses on implementing healthy eating habits, easing restrictions, and reintroducing foods. The final phase is maintenance, which aims to keep the lost weight off.  

    Medifast 5 & 1 Plan: Consists of six meals a day: five Medifast meals that are 90-110 calories and one lean & green meal created by the member consisting of one lean protein and three servings (1/2 cup) of Medifast-approved non-starchy vegetables.

    Transition: Introduces a different food group each week to gradually increase your calorie intake while the number of Medifast meals per day decreases. The number of calories depends on height, weight, gender, lean muscle mass, and activity level. Stage one introduces vegetables, stage two fruits, stage three dairy, and stage four whole grains.

    Maintenance: Focuses on finding your specific calorie needs and then balancing them to match your food intake with calories burned to ensure weight maintenance. You continue to eat Medifast meals, vegetables, fruits, healthy fats, dairy, and whole grains at this stage.  


    The Medifast diet has been phased out, and similar weight loss plans have been rebranded under the company OPTAVIA. The current price of the OPTAVIA 5 & 1 plan is $378.25 for 119 serves; this will last just over three weeks. However, this does not include the daily lean and green meal cost.

    Dos and Don’ts

    A quick checklist of dos and don’ts to ensure you stick to your plan.


    • Stay hydrated
    • Eat six meals a day
    • Exercise daily
    • Be mindful of portion sizes


    • Skip meals
    • Drink alcohol

    Sample Diet Plan

    A sample of a 5 & 1 plan provides you with an idea of the foods Medifast offer:

    Meal 1 – Breakfast

    • Medifast oatmeal

    Meal 2 – Mid-morning

    • Medifast cappuccino

    Meal 3 – Lunch: Lean and green meal

    • Turkey mince and mixed salad

    Meal 4 – Mid-afternoon

    • Medifast pretzel sticks

    Meal 5 – Dinner

    • Medifast beef stew  

    Meal 6 – Evening

    • Medifast chocolate pudding

    Transition Diet Plan:

    During the transition stage, the number of Medifast meals slowly decreases, and new food groups increase.

    Week 1 Vegetables: 5 Medifast meals, one lean and green, and add 1 cup of any vegetable

    Week 2 Fruits: 4 Medifast meals, one lean and green; add 1 cup of any vegetable, two medium-sized pieces of fruit, or 1 cup of cubed fruit or berries

    Week 3 Dairy: Same as above, and add one cup of low-fat or fat-free dairy

    Week 4 Whole Grains: 3 Medifast meals, one lean and green, and add 4 to 6 servings of lean meat and one serving of whole grain

    Maintenance Diet Plan:

    The maintenance Medifast program varies greatly depending on your calorie needs, ranging from 1200 to 3000 calories per day. Still, all plans consist of Medifast meals, grains, vegetables, fruit, meat and meat substitutes, milk, and fat in varying servings.

    Meal 1 – Breakfast

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    • Two scrambled eggs with 1 cup spinach and one whole-grain toast

    Meal 2 – Mid-morning

    • Medifast chocolate shake with one banana  

    Meal 3 – Lunch

    • Medifast tomato soup with ½ cup of vegetables

    Meal 4 – Mid-afternoon

    • Medifast caramel bar

    Meal 5 – Dinner

    • Chicken breast with ½ cup corn and 1 cup broccoli and cauliflower

    Meal 6 – Evening

    • Plain yogurt and ½ cup fresh fruit

    Health Benefits and Drawbacks


    The Medifast diet does result in impressive weight loss. Medical professionals have shown interest in the diet for a rapid weight loss intervention for obese adults. In a study of 120 obese men and women following either the Medifast or reduced energy food-based diet, the Medifast diet resulted in greater body weight and fat loss compared with a food-based diet at the end of the weight loss phase and maintained greater weight loss for one year.

    A further benefit of the Medifast diet is the enforcement of portion control through meal replacements. Creating a structured diet reduces the risk of large portions and poor food choices, helping to avoid weight gain.

    The diet is convenient and easy to follow, leading to greater adherence, weight loss, and satisfaction. Research showed that more dieters completed a diet when following the Medifast diet compared to similar weight loss programs.


    The most followed and well-known Medifast 5 & 1 weight loss plan avoids entire food groups, including dairy, fruit, and starches. The core aspect of a healthy diet is to eat a nutritious, balanced diet from various food groups, ensuring your body receives all essential nutrients. The diet is strict, limiting, and hard to sustain long-term.

    Rapid weight loss comes with serious side effects, which is why the program advises medical monitoring by professionals. Medifast warns of some side effects: constipation, cramps, light-headedness, fatigue, rashes, and dry skin or hair. A study found participants following the diet reported fatigue and constipation.

    The biggest red flag about the Medifast diet is it is not backed by sound or strong research. The few publicly available studies have been sponsored by the company Medifast, which raises serious concerns about the findings.  

    The Bottom Line: Is the Medifast Diet a Healthy Way to Lose Weight?

    The bottom line is the Medifast diet is an unhealthy way to meet your weight loss goals. The diet eliminates key food groups, has serious side effects, and is not backed by scientific studies that credit the safety of the diet.

    Disclaimer: The information on this website is for informational purposes only. No material on this site is intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare providers with any questions you may have regarding a medical condition or treatment before undertaking a new healthcare regimen.
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