What Can I Eat While on OPTIFAST?

November 16, 2025 •

4 min read

Over 80 global clinical papers demonstrate the safety and effectiveness of the OPTIFAST program for weight loss. A key part of success is understanding what can I eat while on OPTIFAST, which is determined by the specific phase of the very low-calorie diet (VLCD) plan.

Quick Summary

A guide detailing the specific foods and beverages permitted across the different phases of the OPTIFAST VLCD program, from the restrictive Intensive phase to the more flexible Transition, Active, and Maintenance phases. This plan is medically supervised and incorporates low-starch vegetables, fluids, and eventually, low-calorie meals to support weight loss and long-term management.

Key Points

Intensive Phase: Eat three OPTIFAST products daily, plus two cups of low-starch vegetables and one teaspoon of vegetable oil, for rapid weight loss.
Active Phases: Reintroduce healthy, low-calorie meals, lean protein, and small portions of fruit and dairy as you progress through the Active 2 and Active 1 levels.
Low-Starch Vegetables: Allowed vegetables like broccoli, spinach, and mushrooms can be eaten in moderation to provide fiber and nutrients across all program levels.
Calorie-Free Fluids: Drink a minimum of two liters of water, black coffee, or unsweetened tea daily to stay hydrated and support your kidneys.
Flavoring Options: Utilize calorie-free condiments such as lemon juice, vinegar, herbs, and spices to add variety without extra calories.
Ketosis Management: Adhering strictly to the food list is crucial during the Intensive phase to maintain ketosis, which naturally suppresses appetite.
Medical Supervision: The OPTIFAST program, particularly the intensive VLCD portion, should be used under the supervision of a healthcare professional.

Understanding the OPTIFAST Program Levels

The OPTIFAST VLCD (Very Low-Calorie Diet) program is a medically supervised weight management plan designed to replace meals with nutritionally complete OPTIFAST products. The diet progresses through several phases, with the allowance of additional foods increasing with each step. It is crucial to follow the guidelines for your specific level to ensure the diet's effectiveness and your safety.

The Intensive Phase (Very Low Calorie Diet)

This initial phase is the most restrictive and is designed for rapid weight loss, typically lasting up to 12 weeks. During this time, your daily calorie intake is restricted to between 600 and 800 calories. In addition to three daily OPTIFAST VLCD products, only specific, low-calorie extras are permitted. This level induces a state of ketosis, which can help suppress appetite.

Allowed Food on Intensive Phase

Low-Starch Vegetables: Up to two cups per day can be consumed, either raw or cooked. Examples include:
- Asparagus
- Broccoli
- Cabbage
- Cauliflower
- Celery
- Cucumber
- Lettuce
- Mushrooms
- Spinach
Vegetable Oil: One teaspoon of vegetable oil is recommended per day.
Fluids: At least two liters of water or other calorie-free fluids must be consumed daily. This includes water, soda water, plain mineral water, decaf coffee, or decaf tea (with no milk or sugar).
Condiments: A small amount of calorie-free dressings, herbs, and spices can be used for flavour. This includes vinegar, lemon and lime juice, soy sauce, garlic, and pepper.
Soups: Miso soup or broth made from allowed vegetables is permitted.
Other Additions: Artificial sweeteners, diet jelly, and flavour extracts are typically allowed to enhance your OPTIFAST products.

Foods to Avoid in the Intensive Phase

High-starch vegetables like corn, peas, and potatoes
Legumes and lentils
Fruit and fruit juice
Dairy products
Sugary drinks and alcohol
Creamy sauces and high-calorie dressings

Transitioning to Other Program Levels

As you progress through the program, more food is gradually reintroduced to prepare you for long-term weight management. In the Active 2 level, you replace two meals with OPTIFAST and eat one healthy meal, while Active 1 involves one OPTIFAST meal and two healthy meals.

What to Eat as the Diet Advances

Active 2 Phase: In addition to two OPTIFAST products, you will have one healthy, low-calorie meal of around 350-400 calories. This meal should consist of lean protein, low-starch vegetables, and a small portion of low-GI grains. One fruit and one dairy serving are also introduced.
Active 1 Phase: Here, you will have two low-calorie meals of around 350-400 calories and one OPTIFAST product. This phase allows for two fruit servings and one dairy serving daily, alongside low-starch vegetables.
Maintenance Phase: For long-term management, you eat three healthy, calorie-controlled meals daily, with OPTIFAST products used as needed to manage weight.

Intensive vs. Active Phases: A Comparison


Feature	Intensive Phase	Active Phases (2 & 1)
OPTIFAST Products	3 per day (total meal replacement)	2 or 1 per day
Low-Calorie Meals	None, except for low-starch vegetables	1 meal (~350 kcal for Active 2), 2 meals (~350 kcal each for Active 1)
Calorie Range	600-800 kcal/day	1000-1200 kcal/day
Low-Starch Vegetables	At least 2 cups per day	At least 2 cups per day
Fruit Allowance	No fruit	1 serving (Active 2), 2 servings (Active 1)
Dairy Allowance	No dairy	1 serving
Vegetable Oil	1 teaspoon per day	Included in low-calorie meals
Metabolic State	Induces ketosis	Uses calorie restriction, not ketosis

Conclusion: Navigating Your OPTIFAST Journey

Knowing what to eat while on OPTIFAST is paramount for achieving your weight loss goals and transitioning to a healthy lifestyle. The program is carefully structured, starting with a restrictive intensive phase that focuses on OPTIFAST products and low-starch vegetables, before gradually reintroducing other foods in the active and maintenance phases. It is essential to understand the rules for your current phase and to consult with a healthcare professional to ensure safe and effective weight management. By adhering to the guidelines, you can maximize your results and build the foundation for long-term success.

Staying on Track: Practical Tips

Hydrate Adequately: Drink plenty of water throughout the day to support your kidneys and aid in satiety.
Plan Ahead: Prepare your meals and snacks in advance to avoid impulsive or unhealthy choices, especially when you are away from home.
Utilize Seasoning: Use allowed herbs, spices, and calorie-free condiments to add variety and flavour to your food without adding extra calories.
Track Your Intake: Keeping a food diary can help you stay accountable and monitor your consumption accurately.
Choose Wisely at Restaurants: When dining out during the active phases, research menus beforehand and opt for grilled lean protein and large salads with dressing on the side.

Example Meal Planning

To help visualize, a day in the Active 2 phase might look like:

Breakfast: One OPTIFAST VLCD Shake
Lunch: One cup of low-starch vegetables and one OPTIFAST VLCD Bar
Dinner: A lean protein portion (e.g., 100g grilled chicken), a large portion of steamed broccoli and spinach, and a small serving of brown rice, totalling around 350-400 calories.
Snacks: One serving of fruit (e.g., a small apple) and one serving of low-fat dairy (e.g., a small tub of low-fat yogurt).

By following these guidelines and tips, you can successfully navigate the OPTIFAST program and achieve your weight loss goals.

Visit the OPTIFAST website for official product and program information.

Frequently Asked Questions

No, fruit is not permitted during the Intensive phase due to its higher carbohydrate and calorie content, which can affect ketosis. Fruit is gradually reintroduced in the later Active phases.

No, alcohol should be avoided, especially during the Intensive phase, as it can disrupt the program's effectiveness. Instead, opt for water with lemon or diet soft drinks in a wine glass during social situations.

You can eat low-starch vegetables, such as asparagus, broccoli, spinach, cabbage, and cauliflower. High-starch vegetables like potatoes, corn, and peas should be avoided.

No, the OPTIFAST VLCD program is formulated to provide all necessary daily vitamins and minerals, so additional supplementation is not required unless you have a pre-existing deficiency diagnosed by a healthcare provider.

Constipation can occur due to low fiber intake. Increase your water consumption to 2-3 liters, ensure you consume the full allowance of low-starch vegetables, and consider a fiber supplement like psyllium husk if needed.

Yes, you can add zero-calorie flavor extracts, sugar-free syrups, or instant coffee crystals to your shakes to add variety. You can also use herbs and spices to season your allowed vegetables.

Appetite is often suppressed after the first few days due to ketosis in the Intensive phase. Ensure you drink enough fluids, eat your full portion of allowed low-starch vegetables, and distinguish true hunger from emotional triggers like stress or boredom.