The Fast 800 diet, popularized by Dr. Michael Mosley, is a low-calorie eating plan designed for rapid weight loss and metabolic health improvements. It is not a long-term diet but rather an intensive, short-term phase to kick-start weight loss, typically followed for a maximum of 12 weeks under supervision, before transitioning to a more moderate approach. The core principle is to consume roughly 800 calories per day from high-quality, nutrient-dense foods based on a Mediterranean-style diet.
Core Food Groups to Focus On
To make every calorie count, meals should be built around satisfying, whole foods rich in protein, healthy fats, and fiber. These components help control hunger and keep blood sugar levels stable, which is key to success on a calorie-restricted plan.
- High-Quality Protein: Essential for muscle maintenance and promoting a feeling of fullness. Sources include lean meats like chicken and turkey, fish (especially oily fish like salmon and mackerel), eggs, tofu, and legumes such as lentils and chickpeas.
- Healthy Fats and Oils: Crucial for satiety and overall health, healthy fats also aid in the absorption of fat-soluble vitamins. Include extra virgin olive oil for cooking and dressing, as well as avocados, nuts, and seeds in small quantities.
- Fiber-Rich Vegetables: Non-starchy vegetables can be eaten in abundance and without counting their calories, as they are very low in energy and high in fiber, vitamins, and minerals. Fill your plate with leafy greens, broccoli, cauliflower, mushrooms, peppers, and zucchini.
- Low-Sugar Fruits: Berries (strawberries, blueberries, raspberries) are excellent choices for their high fiber and antioxidant content, while apples and pears are also recommended. Sweet, tropical fruits should be avoided due to their higher sugar content.
- Full-Fat Dairy: Unlike older diet theories, the Fast 800 advocates for full-fat dairy products like Greek yogurt and some cheeses. The higher fat content provides better satiety, and these products are less likely to be stripped of nutrients and laden with sugar.
Foods to Avoid on the 800 Fast Diet
Equally important is knowing which foods to minimize or avoid entirely to prevent cravings and blood sugar spikes. These are typically the highly processed and sugary options that provide little nutritional value.
- Refined Carbohydrates: White bread, pasta, and rice are rapidly broken down into sugar in the body, which can cause cravings and fat accumulation. Instead, opt for complex carbohydrates like quinoa or brown rice in very small, controlled portions.
- Added Sugars and Sweets: This includes sugary drinks, baked goods, candy, and many processed foods. These empty calories offer no satiety and can derail progress.
- Low-Fat Products: Many low-fat versions of foods have added sugars and other additives to compensate for flavor. Opt for the full-fat, natural versions instead for better satiety and nutrition.
- Snacking: Snacking between meals can spike insulin levels. The focus on nutrient-dense meals is intended to keep you full and satisfied throughout the day without the need for snacks.
A Sample Daily 800-Calorie Meal Plan
To illustrate how these food groups can come together, here is a sample day for the intensive phase of the diet, totaling approximately 800 calories.
- Breakfast (approx. 200 kcal): Scrambled eggs (2 large) with a handful of spinach and mushrooms cooked in a teaspoon of olive oil.
- Lunch (approx. 350 kcal): A large mixed green salad topped with grilled chicken breast (100g), cucumber, and cherry tomatoes, drizzled with a tablespoon of extra virgin olive oil and lemon juice dressing.
- Dinner (approx. 250 kcal): Stir-fried tofu with bell peppers, broccoli, and a small amount of sesame oil.
Healthy Choices vs. Suboptimal Choices
This table summarizes the core food philosophy of the 800 fast diet, emphasizing Mediterranean-style, whole foods over processed alternatives.
| Best Choices on 800 Fast Diet | Foods to Minimize or Avoid |
|---|---|
| Lean proteins (fish, chicken, eggs, tofu) | Processed meats (bacon, salami) |
| Healthy fats (avocado, olive oil, nuts) | Low-fat products (dressings, yogurts) |
| Non-starchy vegetables (spinach, broccoli) | Sugary drinks and desserts |
| Low-sugar fruits (berries, pears) | Sweet tropical fruits (mango, pineapple) |
| Whole, natural foods | Ultra-processed foods |
| Water, herbal tea, black coffee | Sugary drinks, fruit juice with added sweeteners |
Important Considerations for Success
Hydration
Staying hydrated is non-negotiable on a low-calorie diet. It can help curb hunger, manage cravings, and keep your body functioning optimally. Drink plenty of water throughout the day. Herbal teas and black coffee are also excellent options and will not add to your calorie count.
Exercise
While on the intensive phase, intense exercise is generally not recommended due to low calorie intake. However, gentle exercise like walking or yoga can boost mood and metabolic health. As you transition to less restrictive phases, incorporating more strenuous activities is encouraged.
Mindful Eating
Practicing mindful eating can significantly aid in hunger management. Eating slowly and savoring your meals helps your body register fullness more effectively, preventing feelings of deprivation on a reduced calorie plan.
What Happens After the Fasting Period?
The Fast 800 is not designed to be followed forever. The goal is to establish new, healthier eating habits based on the Mediterranean diet. After the initial phase, participants transition to a maintenance plan, such as the 5:2 approach (800 calories two days a week) or the Way of Life, which focuses on sustainable, balanced eating without strict calorie counting. This gradual shift helps prevent the 'rebound' effect common with crash diets and ensures long-term success.
Conclusion
Navigating what to eat on the 800 fast diet requires a strategic focus on nutrient density. By prioritizing lean proteins, healthy fats, and a wide array of vegetables, you can create satisfying and nutritionally sound meals within the calorie limit. Remember to focus on whole, unprocessed foods and stay well-hydrated to make your short-term weight loss journey as successful and comfortable as possible. This approach is not just about calorie restriction, but about resetting your relationship with food to build a healthier, more sustainable lifestyle moving forward.
