Understanding the Fast 800 Approach
Developed by Dr. Michael Mosley, the Fast 800 is a flexible dietary program that can involve different phases, from rapid weight loss to sustainable maintenance. The core principle, especially for intermittent fasting or the 'Very Fast 800' phases, is a calorie restriction to 800 calories per day on designated fasting days. To ensure success and prevent nutrient deficiencies, the diet emphasizes consuming whole, natural foods that are high in protein, healthy fats, and fiber. This approach aims to induce a mild ketosis, switching the body from burning sugar to burning fat for fuel, which helps curb appetite.
The Building Blocks of a Fast 800 Day
Prioritize High-Quality Protein
Protein is your best friend on a low-calorie day because it helps you feel full for longer and prevents muscle loss during weight loss. Your 800-calorie day should include 50-60g of high-quality protein.
- Eggs: Boiled, poached, scrambled, or in an omelette, eggs are a versatile breakfast option that provides lasting satiety.
- Lean Meats and Poultry: Skinless chicken breast, turkey, and lean cuts of pork or beef are excellent choices.
- Fish: Oily fish like salmon, mackerel, and sardines are packed with protein and healthy omega-3 fats.
- Tofu: A plant-based source of protein that works well in stir-fries and salads.
- Legumes: Chickpeas, lentils, and beans add both protein and fiber to your meals.
- Dairy: Full-fat Greek yogurt and cottage cheese provide protein and healthy fats, and keep you satisfied.
Load Up on Non-Starchy Vegetables
Non-starchy vegetables are the foundation of your Fast 800 day. You can eat a generous portion of these without needing to count the calories, as they add bulk, fiber, and nutrients for very few calories.
- Leafy Greens: Spinach, kale, rocket, and lettuce are essential for salads and wilting into dishes.
- Cruciferous Vegetables: Broccoli, cauliflower, and Brussels sprouts are high in fiber and nutrients.
- Other Vegetables: Mushrooms, aubergine (eggplant), peppers, zucchini, and cucumbers add variety and flavour.
Include Healthy Fats in Moderation
Healthy fats are crucial for satiety and overall health, even on a low-calorie day. They help control blood sugar and provide essential vitamins.
- Extra Virgin Olive Oil: Use it sparingly for cooking or as a salad dressing.
- Avocado: A great source of healthy fats that can be added to salads or eggs.
- Nuts and Seeds: A small handful of almonds, walnuts, chia seeds, or flaxseeds can add healthy fats and fiber.
Sample Day Meal Plan (~800 calories)
Here is an example of what a day on the Fast 800 might look like, focusing on high-volume, nutrient-dense meals.
- Breakfast (~200 calories): A generous omelette made with two eggs, a handful of spinach, mushrooms, and a sprinkle of grated parmesan cheese, cooked in a teaspoon of olive oil.
- Lunch (~300 calories): A vibrant salad with grilled chicken breast (about 100g), mixed greens, cucumber, and cherry tomatoes, drizzled with a simple lemon and olive oil vinaigrette.
- Dinner (~300 calories): Baked salmon fillet (around 100g) served with a large side of steamed broccoli and asparagus.
Fast 800 Food Choices: A Comparison
To help visualize better food choices, here is a comparison table of items to embrace versus those to avoid on your fasting day.
| Food Group | Embrace on Fasting Day | Avoid on Fasting Day |
|---|---|---|
| Protein | Lean chicken, turkey, salmon, eggs, tofu, Greek yogurt, chickpeas | Processed meats (bacon, salami), sugary protein bars |
| Vegetables | All non-starchy vegetables like leafy greens, broccoli, peppers, zucchini | Starchy vegetables like white potatoes, sweetcorn |
| Fats | Extra virgin olive oil, avocado, small portions of nuts and seeds | Industrial seed oils, margarine, deep-fried foods |
| Carbohydrates | Quinoa and brown rice (in very small, controlled portions if needed) | Refined grains like white bread, pasta, white rice, breakfast cereals |
| Fruits | Berries, apples, pears (in moderation due to sugar content) | Sweet tropical fruits like mango, pineapple, and melon |
| Drinks | Water, herbal teas, black coffee, black tea | Sugary sodas, fruit juices, milkshakes, alcohol |
| Snacks | Non-starchy veggies, a small amount of nuts, sliver of cheese | Biscuits, crisps, sugary treats, cakes |
The Role of Meal Replacements and Hydration
Some versions of the Fast 800 incorporate meal replacement shakes to simplify calorie counting and ensure adequate nutrient intake. However, the emphasis is always on whole, natural foods. If you do opt for shakes, limit them to no more than two per day to keep focus on eating real food.
Staying well-hydrated is absolutely essential. Aim for 2-3 liters of calorie-free liquids per day, such as water, black coffee, or herbal tea. This helps combat common side effects like headaches and constipation that can occur from calorie restriction and dehydration.
Planning for Success and Transitioning
To make your Fast 800 day manageable, planning is key. Prepare your meals in advance, have your high-volume vegetables ready, and stock up on approved snacks like nuts or a sliver of cheese to manage hunger pangs. Remember that the Very Fast 800 phase should not be followed long-term and is recommended for a maximum of 12 weeks under medical supervision. After this intensive phase, the diet transitions to a more sustainable Mediterranean-style eating pattern (The New 5:2 or Way of Life).
For more resources and guidance on the Fast 800 diet, consider visiting the official website. The Fast 800
Conclusion
Successfully navigating a Fast 800 day is all about making smart, nutrient-dense food choices. By prioritizing high-protein foods, fiber-rich non-starchy vegetables, and healthy fats, you can manage hunger and fuel your body effectively within the 800-calorie limit. Focusing on these whole foods, staying hydrated, and planning ahead are the most critical steps to achieving your weight loss goals on this program while maintaining your metabolic health.
