What do you eat on OPTIFAST?: A Comprehensive Guide to the VLCD Program

Research has shown that following the Intensive Level of the OPTIFAST program can lead to an average weight loss of 1.0–2.5 kg per week. To achieve this, dieters must follow a structured, multi-phase plan, which dictates exactly what do you eat on OPTIFAST, from meal replacements to reintroducing solid foods.

Quick Summary

The OPTIFAST diet is a medically supervised program with distinct phases, utilizing nutritionally complete meal replacements and specific food allowances for effective weight loss and long-term management.

Key Points

• Phased Approach: The program consists of four distinct levels: Intensive, Transition, Maintenance, and Stabilization, each with specific dietary guidelines.

• Intensive Phase Diet: Primarily consists of 3 OPTIFAST VLCD products daily, supplemented with low-starch vegetables and a small amount of oil for very low-calorie intake.

• Gradual Reintroduction: In later phases (Transition and Maintenance), you gradually replace OPTIFAST products with calorie-controlled meals, adding fruits and dairy.

• Allowed Foods: Low-starch vegetables like broccoli, spinach, and cauliflower are encouraged throughout the program to provide fiber and nutrients.

• Role of Ketosis: The Intensive Level is designed to induce mild ketosis, which helps suppress appetite and promotes rapid fat loss.

• Product Variety: A range of OPTIFAST products, including shakes, soups, bars, and desserts, offer flexibility and flavor options.

• Professional Guidance: The OPTIFAST program is meant to be followed under the supervision of a healthcare professional to ensure it is suitable for your specific health needs.

The Four Phases of the OPTIFAST Program

OPTIFAST is a very low-calorie diet (VLCD) program structured around four progressive phases. The specific foods you consume change significantly as you move from the initial intensive weight-loss phase to long-term stabilization. While the program can be customized with a healthcare professional, the standard progression is from Intensive to Transition, Maintenance, and finally, Stabilization.

Intensive Level: The VLCD Kickstart

This phase is designed for rapid weight loss and typically lasts up to 12 weeks. It restricts energy intake to under 800 calories per day to induce ketosis, which helps manage appetite.

Daily intake includes:

• 3 OPTIFAST VLCD products (shakes, soups, bars, or desserts)
• 2 cups of allowed low-starch vegetables
• 1 teaspoon of vegetable oil
• 2 liters of water or calorie-free fluids

Transition Level: Reintroducing Whole Foods

Lasting a minimum of two weeks, this phase gradually reintroduces normal foods with a daily intake of 800–1000 calories.

Daily intake includes:

• 2 OPTIFAST VLCD products
• 1 low-calorie meal (350–400 calories) with lean protein and low-starch vegetables
• 2 or more cups of low-starch vegetables
• 1 serve of fruit
• 1 serve of dairy
• 2 liters of water or calorie-free fluids

Maintenance Level: Sustaining Weight Loss

This level increases caloric intake to 1000–1200 calories per day to stabilize weight and build healthy habits.

Daily intake includes:

• 1 OPTIFAST VLCD product
• 2 low-calorie meals (350–400 calories each)
• 2 or more cups of low-starch vegetables
• 2 serves of fruit
• 1 serve of dairy
• 2 liters of water or calorie-free fluids

Stabilization Level: Maintaining a Healthy Lifestyle

In this final stage, all OPTIFAST products are replaced with a food-based diet of 1200–1500 calories per day, focusing on balanced, portion-controlled meals for long-term weight maintenance.

The OPTIFAST Product Lineup

OPTIFAST offers a variety of nutritionally complete meal replacement products. These include shakes, soups, bars, and desserts designed to provide essential nutrients during the low-calorie phases.

Allowed and Prohibited Foods

Specific food choices are important throughout the program, particularly in the intensive phase, to support weight loss. Allowed low-starch vegetables include items like asparagus, broccoli, and spinach, while starchy vegetables and legumes like corn and potatoes are prohibited. Adequate fluid intake of at least 2 liters of water, herbal tea, or black coffee is recommended, and flavorings like herbs and spices are permitted. For a detailed list of allowed and prohibited foods across the program phases, please refer to {Link: Nestle Health Science https://www.nestlehealthscience.com/brands/optifast} or consult the program's guidelines.

A Comparison of OPTIFAST Program Phases

Feature	Intensive Phase	Transition Phase	Maintenance Phase
OPTIFAST Products	3 per day (total meal replacement)	2 per day (replaces two meals)	1 per day (replaces one meal)
Caloric Intake	600–800 calories per day	800–1000 calories per day	1000–1200 calories per day
Whole Foods	2+ cups low-starch vegetables + 1 tsp oil	1 low-calorie meal (~350-400 kcal) + 2+ cups low-starch vegetables, 1 fruit, 1 dairy	2 low-calorie meals (~350-400 kcal) + 2+ cups low-starch vegetables, 2 fruits, 1 dairy
Goal	Rapid initial weight loss	Gradual reintroduction of food	Stable, long-term weight management
Ketosis	Yes, induces mild ketosis	No, works via calorie restriction	No

Conclusion: A Structured Approach to Weight Loss

The OPTIFAST diet provides a clear, structured framework for weight loss by outlining exactly what you eat throughout its progressive phases. From the very low-calorie intensive phase, which relies on nutritionally complete meal replacements, to the transition and maintenance stages, the program guides you toward long-term, sustainable habits. While the meal replacements are the central component, the gradual reintroduction of whole foods—like low-starch vegetables, lean proteins, fruits, and dairy—is key to achieving lasting results and a healthier lifestyle.

For additional resources, you can visit the official {Link: Nestlé Health Science: OPTIFAST https://www.nestlehealthscience.com/brands/optifast} website to learn more about the scientific basis of the program.

Frequently Asked Questions

Is Optifast a ketogenic diet?

The Intensive Phase of the OPTIFAST program is designed to induce a mild state of ketosis, a metabolic process where the body burns fat stores for energy instead of carbohydrates. This is not the case for all phases, however, as regular food is introduced later.

What happens during the "3-Day Challenge" on Optifast?

The first few days on the Intensive Level are often called the "3-Day Challenge." During this time, your body adjusts to using fat for energy, and you may experience temporary side effects like headaches, fatigue, or hunger.

Are there side effects of the Optifast program?

Yes, some people may experience mild, temporary side effects, especially during the initial Intensive phase. These can include headaches, fatigue, bad breath (halitosis), constipation, or diarrhea, but they typically pass as your body adjusts.

Can I have coffee while on Optifast?

Yes, you can have black coffee or tea, but without added milk or sugar. It's important to keep track of your caffeine intake, as giving it up can sometimes contribute to headaches during the initial phase.

Do I have to do all the phases of the Optifast program?

The program's flexibility allows a healthcare professional to tailor the plan to your needs, but moving through the phases is recommended. You can sometimes start on the Active 1 or Active 2 level if the Intensive phase is not right for you.

What types of OPTIFAST products are available?

The OPTIFAST product range includes a variety of nutritionally complete items to replace meals, such as shakes, soups, bars, and desserts, available in multiple flavors.

What's the difference between the Intensive and Maintenance phases?

The Intensive phase is a very low-calorie diet using only Optifast products and limited vegetables, aiming for rapid weight loss. The Maintenance phase replaces only one meal with an Optifast product and includes two low-calorie meals, focusing on sustaining weight loss.