800 Calorie Diet Plan: What the Clinical Evidence Says

Quick Answer

The 800-calorie diet is a Very Low Calorie Diet (VLCD) with a real clinical evidence base for type 2 diabetes remission, when run for 8 to 12 weeks under medical supervision. It is not a casual weight-loss plan. The NHS Path to Remission program uses 800 to 900 kilocalories per day for 12 weeks under structured clinic care. Outside that supervised context, self-directed 800-calorie eating should be limited to 1 to 2 weeks at most, and several groups should not do it at all.

This guide covers what the protocol actually is, what the trials show, who it’s appropriate for, who must avoid it, and how to set up a 7-day meal plan that hits the calorie target without falling into the nutritional gaps that trip most self-directed attempts.

The short version:

Clinical protocols run 8 to 12 weeks under supervision (NHS Path to Remission, Mosley Fast 800)
Sustained weight loss in trials averages 1 to 1.5 kg (2 to 3 lbs) per week, not the higher figures often quoted online
Primary clinical use case: type 2 diabetes remission in adults with obesity
Contraindicated for pregnancy, breastfeeding, type 1 diabetes, BMI under 30, eating disorder history, and several medications
Formula meal replacements (the NHS approach) hit micronutrient adequacy more reliably than food-based plans

What the 800-Calorie Diet Actually Is

The “800-calorie diet” is shorthand for any structured eating plan that limits daily intake to roughly 800 kilocalories. By clinical definition, this falls into the Very Low Calorie Diet category, which the World Health Organization defines as any plan under 800 kcal per day. The protocol is sometimes called a “low energy diet” or “total diet replacement” when formula products are used.

The version most people search for traces back to two specific medical contexts.

The first is the DiRECT trial (Lean et al., The Lancet, 2018), a UK randomized controlled trial that put adults with type 2 diabetes on a 12-week formula diet of 825 to 853 kcal per day under primary-care supervision. At 12 months, 46% of participants in the intervention group had achieved type 2 diabetes remission, compared with 4% in the control group. That trial became the basis for the NHS Path to Remission program, which now runs nationally in England.

The second is The Fast 800, the consumer version popularized by Dr. Michael Mosley, drawing on the DIAMOND study at Oxford (Bailey Mosley et al.). DIAMOND tested an 8-week 800-calorie Mediterranean-style protocol in adults with type 2 diabetes; participants lost an average of 9.5 kg over 8 weeks, with significant improvements in blood sugar, blood pressure, and medication use.

Both protocols cap the 800-calorie phase at 12 weeks. Both follow it with a structured maintenance phase at higher calorie intake (typically 1,500 to 2,000 kcal Mediterranean-style). And both treat the 800-calorie phase as a clinical intervention, not a long-term lifestyle.

Who the 800-Calorie Diet Is For

The clinical evidence base is for one specific group: adults with type 2 diabetes and obesity (typically BMI of at least 27 in NHS criteria, or 30 in most other contexts), who are willing to do the protocol under supervision and follow it with a structured maintenance phase.

Outside that group, the evidence is weaker. The protocol can produce rapid weight loss in non-diabetic adults with obesity, but the long-term outcomes are less well-studied than the diabetes remission case. For someone with a normal-range BMI looking to lose 5 kg, an 800-calorie diet is the wrong tool. It’s clinical-grade restriction for a problem that doesn’t need it, and the rebound risk is high.

If your goal is general weight loss without an underlying metabolic condition, a moderate calorie deficit (250 to 500 kcal below maintenance) sustained over months produces better long-term outcomes than a short-burst 800-calorie protocol followed by regain.

Who Should Not Follow an 800-Calorie Diet

The contraindications are specific and they matter. If any of these apply, this protocol is the wrong choice for you.

Pregnant or breastfeeding women. Pregnancy requires a minimum of 175 g of carbohydrate per day for fetal development. An 800-calorie diet cannot meet that.
Type 1 diabetes, especially during pregnancy. Insulin requirements change unpredictably at this calorie level. T1D in pregnancy is an absolute contraindication.
BMI under 30. Clinical 800-calorie protocols are designed for adults with obesity. Below BMI 30, the risk-benefit shifts sharply against the protocol.
Eating disorder history or active disordered eating. Restrictive protocols at this level are documented triggers for relapse. Talk to your treatment team before considering this.
People taking insulin, sulfonylureas, or SGLT2 inhibitors. These need to be adjusted in advance by a physician, otherwise hypoglycemia risk is significant.
Fertility treatment. Not recommended.
Children, teenagers, and anyone under 18. Growth requirements are not compatible with this calorie level.
Significant kidney, liver, or cardiac disease. Specialist clearance required.

If you fit any of these and you’re considering this protocol because of online content (including this article), please talk to your physician or a registered dietitian before starting.

What the Trials Actually Show About Weight Loss

You will see “lose 4 to 8 pounds per week” in older articles about the 800-calorie diet. That figure is misleading and worth understanding clearly.

In clinical trials of the 800-calorie protocol, sustained weight loss averages roughly 1 to 1.5 kg (2 to 3 lbs) per week over the 8 to 12 week intensive phase. The first week typically shows higher loss because the body burns through stored glycogen first, and each gram of glycogen holds about 3 grams of water. So a week-one drop of 4 to 6 lbs is real, but most of it is water and glycogen, not body fat. By week 4, the loss rate normalizes to the 1 to 1.5 kg range.

The trial-level numbers worth knowing:

DiRECT trial (12-week intensive phase plus maintenance): average 10 kg loss at 12 months. Participants who achieved diabetes remission lost 15 kg.
DIAMOND study (8-week Mediterranean 800-calorie): average 9.5 kg loss.
NHS Path to Remission real-world data (Lancet Diabetes & Endocrinology, 2024): average 16 kg over the full program (12-week intensive plus 9-month follow-up); about 32% achieved type 2 diabetes remission.

If you do the protocol correctly and follow it with a structured maintenance phase, those are the numbers to expect. If a source promises faster sustained loss than that, the source is overstating it.

Food-Based vs Formula-Based: Why the Difference Matters

The NHS Path to Remission uses formula meal replacements: shakes, soups, and bars from products like Optifast or Lighter Life. The reason is practical. Hitting full micronutrient adequacy at 800 kcal of regular food is genuinely difficult. You’re working with about a third of normal intake, which means everything you eat has to be doing nutrient duty.

A food-based 800-calorie plan can work, but it needs careful planning to avoid:

Protein adequacy gaps (target around 60 to 90 g per day depending on body size)
Iron, B12, calcium, magnesium, and zinc deficiencies
Fiber shortfall (which gets worse on low-carb versions of the protocol)
Electrolyte imbalance (sodium, potassium, magnesium)

If you’re going to do this with food, working with a registered dietitian for at least one planning session is the difference between a defensible protocol and a half-baked attempt that leaves you tired and undernourished. See our note on the difference between a registered dietitian and a nutritionist for what to look for.

Approach Comparison

Approach	Calories/day	Duration	Format	Supervision	Best for
NHS Path to Remission	800–900	12 weeks intensive + 9-month follow-up	Formula meal replacements	Required (NHS clinic)	Adults with type 2 diabetes, BMI ≥27
Mosley Fast 800	~800	2–12 weeks	Low-carb Mediterranean	Recommended	Consumer audience, T2D-adjacent
Self-directed 800-cal (food-based)	~800	Max 1–2 weeks	Regular food	Strongly recommended	Limited use cases
Standard calorie deficit	1,200–1,800	Indefinite	Regular food	Optional	Sustainable weight management

A 7-Day 800-Calorie Meal Plan (Food-Based)

The meal plan below is built on the principle that each meal lands at roughly 270 kcal, totaling 810 kcal, close enough to the 800-calorie target without the false precision of trying to hit it exactly. Protein is prioritized in every meal because the highest-risk macronutrient gap on this protocol is protein adequacy.

This is a starting framework, not a prescription. If you have any of the contraindications listed above, do not use this plan. If you’re going to use it, pair it with the maintenance-phase guidance at the end of this article.

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800 Calorie Meal Plan (General)

General

Meals	Day 1	Day 2	Day 3	Day 4	Day 5	Day 6	Day 7
Breakfast	2 large eggs scrambled, 1 cup wilted spinach with 1 tsp olive oil (220 cal, 14g protein)	1/2 cup cooked oatmeal with 1 tbsp natural peanut butter and 1/2 medium banana (225 cal, 8g protein)	4 oz plain Greek yogurt (0%) with 1 cup strawberries and 1 small slice whole-grain toast (185 cal, 16g protein)	1 large egg poached, 1 small slice whole-grain toast, 1 medium tomato sliced (202 cal, 9g protein)	2-egg omelette with 1 cup wilted spinach and 1 oz crumbled feta (255 cal, 18g protein)	2 large eggs scrambled, 1 medium tomato sliced, 1/2 small slice whole-grain toast (197 cal, 13g protein)	1 cup low-fat cottage cheese with 1 cup strawberries (215 cal, 29g protein)
Snack	4 oz plain Greek yogurt (0%) with 1/4 cup blueberries (105 cal, 12g protein)	1/2 oz raw almonds, about 12 nuts (82 cal, 3g protein)	1 medium apple (95 cal, 0.5g protein)	1/2 oz pumpkin seeds, about 2 tbsp (80 cal, 4g protein)	4 oz plain Greek yogurt (0%) with 1/4 cup blueberries (105 cal, 12g protein)	4 oz plain Greek yogurt (0%) with 1/2 cup strawberries (90 cal, 12g protein)	1/2 oz raw almonds and 1 small clementine (117 cal, 4g protein)
Lunch	3 oz grilled chicken breast, 2 cups mixed greens, 1/4 cup cooked quinoa, 1 medium tomato, lemon (237 cal, 30g protein)	4 oz tuna canned in water, 2 cups mixed greens, 1/4 cup chickpeas, 1 tsp olive oil, tomato and cucumber (290 cal, 33g protein)	3 oz grilled chicken breast, 1 cup steamed cauliflower, 1 tsp olive oil with lemon (210 cal, 28g protein)	4 oz tuna canned in water, 2 cups mixed greens, 1/4 cup chickpeas, 1 tsp olive oil, cucumber (268 cal, 30g protein)	4 oz lean ground turkey with 1 cup mashed cauliflower and 1 tsp olive oil (235 cal, 25g protein)	3 oz grilled chicken breast, 2 cups mixed greens, 1/2 cup mashed cauliflower with 1 tsp olive oil, 1/4 cup cooked brown rice (284 cal, 30g protein)	4 oz tuna canned in water, 2 cups mixed greens, 1/4 medium avocado, 1 tsp olive oil with lemon (250 cal, 30g protein)
Dinner	3 oz baked salmon with 1 cup steamed broccoli and lemon (230 cal, 23g protein)	4 oz lean ground turkey with 1 cup green beans (210 cal, 25g protein)	4 oz pan-seared firm tofu, 1 cup roasted bell peppers, 1 tsp olive oil, 1/2 cup cooked brown rice (323 cal, 19g protein)	3 oz grilled chicken breast, 1 cup roasted asparagus with 1 tsp olive oil (220 cal, 28g protein)	3 oz baked salmon with 1 cup steamed broccoli and lemon (230 cal, 23g protein)	3 oz baked salmon, 1 cup roasted bell peppers, 1 cup roasted asparagus (245 cal, 22g protein)	3 oz grilled chicken breast, 1 cup steamed cauliflower, 1 cup roasted bell peppers (200 cal, 28g protein)
Total calories for the day	792 cal, 79g protein	807 cal, 69g protein	813 cal, 64g protein	790 cal, 71g protein	825 cal, 78g protein	816 cal, 77g protein	782 cal, 91g protein

800 Calorie Meal Plan Variations

Low Carb

Meals	Day 1	Day 2	Day 3	Day 4	Day 5	Day 6	Day 7
Breakfast	2-egg omelette with 1 cup wilted spinach, 1 oz feta, 1/8 medium avocado (285 cal, 18g protein, 3g net carbs)	2 large eggs scrambled with 1 cup mushrooms, 1/2 oz cheddar, 1 tsp olive oil (273 cal, 18g protein, 3g net carbs)	1 cup low-fat cottage cheese with 1/4 cup mixed berries and 1 tbsp slivered almonds (215 cal, 30g protein, 5g net carbs)	2 hard-boiled eggs with 1/2 medium avocado (260 cal, 14g protein, 2g net carbs)	2-egg omelette with 1 cup wilted spinach and 1/2 oz cheddar (238 cal, 18g protein, 2g net carbs)	1 cup low-fat cottage cheese with 1/4 cup blueberries (185 cal, 29g protein, 6g net carbs)	2 large eggs, 2 oz smoked salmon, 1 cup wilted spinach, 1/2 oz cheddar (271 cal, 31g protein, 2g net carbs)
Lunch	3 oz grilled chicken, 2 cups mixed greens, 1/4 medium avocado, 1 tsp olive oil with lemon (260 cal, 28g protein, 3g net carbs)	4 oz tuna canned in water, 2 cups mixed greens, 1/2 medium avocado, 1 tsp olive oil with lemon (310 cal, 30g protein, 4g net carbs)	3 oz grilled chicken, 2 cups mixed greens, 1/4 medium avocado, 1/2 oz raw almonds, 1 tsp olive oil (342 cal, 31g protein, 5g net carbs)	3 oz grilled chicken, 2 cups mixed greens, 1 oz feta, 1 tsp olive oil with lemon (275 cal, 30g protein, 3g net carbs)	4 oz tuna canned in water, 2 cups mixed greens, 1/4 medium avocado, 1/2 oz pumpkin seeds, 1 tsp olive oil (330 cal, 32g protein, 5g net carbs)	3 oz grilled chicken, 2 cups mixed greens, 1/4 medium avocado, 1/4 cup chickpeas, 1 tsp olive oil with lemon (330 cal, 31g protein, 14g net carbs)	4 oz lean ground turkey, 1 cup mushrooms, 1 cup mixed greens, 1 medium tomato, 1 tsp olive oil (272 cal, 26g protein, 5g net carbs)
Dinner	3 oz baked salmon, 1 cup roasted asparagus, 1 cup steamed broccoli, 1 tsp olive oil (310 cal, 23g protein, 9g net carbs)	4 oz lean ground turkey, 1 cup steamed green beans, 1 cup mushrooms, 1 tsp olive oil (285 cal, 25g protein, 6g net carbs)	3 oz baked salmon, 1 cup steamed cauliflower, 1 cup roasted bell peppers, 1 tsp olive oil (275 cal, 22g protein, 7g net carbs)	4 oz baked cod, 1 cup steamed asparagus, 1 cup roasted Brussels sprouts, 1/2 oz raw almonds, 1 tsp olive oil (305 cal, 29g protein, 8g net carbs)	3 oz baked salmon, 1 cup roasted bell peppers, 1 cup roasted zucchini, 1 tsp olive oil (275 cal, 19g protein, 7g net carbs)	4 oz lean ground turkey, 1 cup steamed broccoli, 1 cup mushrooms, 1 tsp olive oil (295 cal, 27g protein, 7g net carbs)	3 oz baked cod, 1 cup roasted asparagus, 1 cup roasted Brussels sprouts, 1/4 medium avocado, 1 tsp olive oil (260 cal, 23g protein, 8g net carbs)
Total calories for the day	855 cal, 69g protein, 15g net carbs	868 cal, 73g protein, 13g net carbs	832 cal, 83g protein, 17g net carbs	840 cal, 73g protein, 13g net carbs	843 cal, 69g protein, 14g net carbs	810 cal, 87g protein, 27g net carbs	803 cal, 80g protein, 15g net carbs

Keto

Day	Breakfast	Snack 1	Lunch	Snack 2	Dinner	Total
1	2 large eggs scrambled with 1 cup wilted spinach (147 cal, 13g protein, 1g net carbs)	1/2 oz macadamia nuts, about 5 nuts (100 cal, 1g protein, 1g net carbs)	3 oz tuna in water, 2 cups mixed greens, 1/2 oz feta, 1 tsp olive oil with lemon (198 cal, 23g protein, 4g net carbs)	1/2 oz cheddar cheese (58 cal, 4g protein, 0.5g net carbs)	3 oz baked salmon, 1 cup steamed broccoli, 1/4 medium avocado (290 cal, 23g protein, 7g net carbs)	793 cal, 64g protein, 13g net carbs
2	1-egg omelette with 1/2 oz cheddar and 1 cup cooked mushrooms (160 cal, 12g protein, 5g net carbs)	1/2 oz raw walnuts, about 7 halves (90 cal, 2g protein, 1g net carbs)	3 oz grilled chicken breast, 2 cups mixed greens, 1/4 medium avocado, 1 tsp olive oil, cucumber (260 cal, 28g protein, 5g net carbs)	1 hard-boiled egg (70 cal, 6g protein, 0.5g net carbs)	3 oz baked cod, 1 cup steamed asparagus, 2 tsp butter (215 cal, 24g protein, 4g net carbs)	795 cal, 72g protein, 15g net carbs
3	4 oz full-fat plain Greek yogurt with 1 tbsp slivered almonds and 1/4 cup blueberries (130 cal, 7g protein, 5g net carbs)	1/2 oz raw pecans, about 10 halves (100 cal, 1.5g protein, 1g net carbs)	3 oz grilled chicken breast, 2 cups mixed greens, 1/4 medium avocado, 1 tsp olive oil with lemon (260 cal, 28g protein, 5g net carbs)	1/2 oz cheddar cheese (58 cal, 4g protein, 0.5g net carbs)	3 oz baked salmon, 1 cup steamed asparagus, 1 tsp butter (250 cal, 23g protein, 4g net carbs)	798 cal, 63.5g protein, 16g net carbs
4	1-egg omelette with 1/4 medium avocado and 1/2 oz cheddar (188 cal, 11g protein, 2g net carbs)	1 hard-boiled egg (70 cal, 6g protein, 0.5g net carbs)	4 oz tuna in water, 2 cups mixed greens, 1 tbsp olive oil, cucumber, lemon (278 cal, 30g protein, 5g net carbs)	1/2 oz pumpkin seeds (80 cal, 4g protein, 1g net carbs)	4 oz baked cod, 1 cup steamed green beans, 1 tsp butter (180 cal, 22g protein, 6g net carbs)	796 cal, 73g protein, 14.5g net carbs
5	2 large eggs scrambled with 1 cup cooked mushrooms in 1 tsp butter (210 cal, 17g protein, 5g net carbs)	1/4 oz raw almonds, about 6 nuts (40 cal, 1.5g protein, 1g net carbs)	3 oz pork tenderloin, 2 cups mixed greens, 1/4 medium avocado, 1 tsp olive oil with lemon (230 cal, 19g protein, 4g net carbs)	1 oz cheddar cheese (115 cal, 7g protein, 0.5g net carbs)	3 oz baked salmon, 1 cup steamed asparagus (215 cal, 23g protein, 4g net carbs)	810 cal, 67g protein, 14.5g net carbs
6	1 large egg poached, 1/4 medium avocado, 1 cup wilted spinach with 1 tsp olive oil (140 cal, 8g protein, 2g net carbs)	1/2 oz macadamia nuts, about 5 nuts (100 cal, 1g protein, 1g net carbs)	4 oz tuna in water, 2 cups mixed greens, 1 oz feta, 1 tsp olive oil with lemon (265 cal, 30g protein, 5g net carbs)	1 hard-boiled egg (70 cal, 6g protein, 0.5g net carbs)	3 oz grilled chicken, 1 cup zucchini noodles, 1 tsp olive oil (210 cal, 27g protein, 4g net carbs)	785 cal, 72g protein, 12.5g net carbs
7	2-egg omelette with 1/2 oz feta and 1 cup wilted spinach (190 cal, 16g protein, 2g net carbs)	1/2 oz raw pecans, about 10 halves (100 cal, 1.5g protein, 1g net carbs)	3 oz baked chicken thigh with skin, 1 cup roasted Brussels sprouts, 1 tsp olive oil (275 cal, 17g protein, 4g net carbs)	1/2 oz cheddar cheese (58 cal, 4g protein, 0.5g net carbs)	3 oz lean grilled beef sirloin, 1 cup cooked zucchini (180 cal, 24g protein, 4g net carbs)	803 cal, 62.5g protein, 11.5g net carbs

Diabetes

Day	Breakfast	Snack 1	Lunch	Snack 2	Dinner	Total
1	2 large eggs poached, 1 cup wilted spinach, 1/2 medium tomato (191 cal, 12.5g protein)	1/2 medium apple with 1 tsp natural peanut butter (80 cal, 1.5g protein)	3 oz baked salmon, 2 cups mixed greens, 1/4 cup chickpeas, lemon (265 cal, 26g protein)	4 oz plain Greek yogurt 0% (65 cal, 12g protein)	3 oz grilled chicken, 1 cup steamed broccoli, 1 cup roasted bell peppers (225 cal, 32g protein)	826 cal, 84g protein
2	1/2 cup cooked steel-cut oats with 1 tbsp ground flax, 1/4 cup blueberries, 4 oz plain Greek yogurt (195 cal, 16g protein)	1/2 oz raw almonds, about 12 nuts (82 cal, 3g protein)	4 oz grilled chicken breast, 2 cups mixed greens, 1/8 medium avocado, cucumber, 1 tsp olive oil with lemon (283 cal, 36g protein)	1 small clementine (35 cal, 0.7g protein)	4 oz baked cod, 1 cup steamed asparagus, 1/2 cup roasted Brussels sprouts, 1 tsp olive oil (225 cal, 26g protein)	820 cal, 82g protein
3	4 oz plain Greek yogurt with 1/2 cup mixed berries, 1 tbsp slivered almonds, 1 tbsp ground flax (165 cal, 14g protein)	1 hard-boiled egg with cucumber slices (78 cal, 7g protein)	3 oz grilled chicken, 2 cups mixed greens, 1/4 cup cooked lentils, 1 tsp olive oil, lemon (258 cal, 32g protein)	1/2 oz pumpkin seeds (80 cal, 4g protein)	4 oz turkey breast, 1 cup roasted bell peppers and zucchini, 1 tsp olive oil (220 cal, 29g protein)	801 cal, 86g protein
4	1-egg omelette with 1 oz feta and 1 cup wilted spinach (185 cal, 13g protein)	1 hard-boiled egg, cucumber and tomato (89 cal, 7g protein)	3 oz grilled chicken, 1 cup mixed greens, 1/4 cup cooked quinoa, 1 cup steamed broccoli (260 cal, 32g protein)	1/2 oz raw walnuts, about 7 halves (90 cal, 2g protein)	4 oz baked cod, 1 cup green beans, 1 cup roasted bell peppers (175 cal, 26g protein)	799 cal, 80g protein
5	1/2 cup low-fat cottage cheese with 1 cup strawberries and 1 tbsp slivered almonds (162 cal, 14g protein)	1/2 medium apple with 1 tsp natural peanut butter (79 cal, 1.5g protein)	3 oz grilled chicken, 2 cups mixed greens, 1/4 cup chickpeas, 1 tsp olive oil (270 cal, 30g protein)	4 oz plain Greek yogurt 0% (65 cal, 12g protein)	3 oz baked salmon, 1 cup steamed asparagus (215 cal, 23g protein)	791 cal, 80g protein
6	2 large eggs scrambled with 1 cup mushrooms and 1/2 cup spinach (195 cal, 18g protein)	1/2 cup low-fat cottage cheese with cucumber slices (90 cal, 14g protein)	3 oz baked salmon, 2 cups mixed greens, 1/2 cup roasted Brussels sprouts, 1 tsp olive oil, lemon (280 cal, 22g protein)	1/2 medium apple (47 cal, 0.3g protein)	3 oz grilled chicken, 1 cup roasted bell peppers, 1 cup steamed asparagus (210 cal, 28g protein)	822 cal, 82g protein
7	1/2 cup cooked steel-cut oats with 1 tbsp ground flax and 1/4 cup berries (130 cal, 7g protein)	4 oz plain Greek yogurt with 1/4 cup berries (85 cal, 12g protein)	3 oz grilled chicken breast, 2 cups mixed greens, 1/4 cup cooked quinoa, 1 medium tomato, lemon (237 cal, 30g protein)	1/2 oz raw almonds (82 cal, 3g protein)	3 oz baked salmon, 1 cup roasted asparagus, 1/2 cup roasted Brussels sprouts, 1 tsp olive oil (277 cal, 23g protein)	811 cal, 75g protein

Vegetarian

Day	Breakfast	Snack 1	Lunch	Snack 2	Dinner	Total
1	2 large eggs scrambled with 1 cup wilted spinach (180 cal, 14g protein)	1/2 cup low-fat cottage cheese with cucumber (90 cal, 14g protein)	1/2 cup cooked lentils, 2 cups mixed greens, 1 tsp olive oil, 1 medium tomato (205 cal, 11g protein)	1 hard-boiled egg with cucumber (78 cal, 7g protein)	4 oz pan-seared firm tofu, 1 cup roasted bell peppers, 1/4 cup cooked brown rice, 1 tsp olive oil (269 cal, 18g protein)	822 cal, 64g protein
2	4 oz plain Greek yogurt with 1/4 cup cooked oats, 1 tbsp slivered almonds, 1/2 cup mixed berries (175 cal, 14g protein)	1/2 cup low-fat cottage cheese with cucumber (90 cal, 14g protein)	4 oz firm tofu, 2 cups mixed greens, 1 tsp olive oil, tomato, cucumber (235 cal, 18g protein)	1 hard-boiled egg (70 cal, 6g protein)	1/2 cup cooked lentils, 1 cup steamed cauliflower, 1 cup roasted bell peppers, 1 tsp olive oil (215 cal, 11g protein)	785 cal, 63g protein
3	1 cup low-fat cottage cheese with 1/2 cup mixed berries and cinnamon (205 cal, 29g protein)	1 hard-boiled egg with cucumber (78 cal, 7g protein)	1/2 cup chickpeas, 2 cups mixed greens, 1 oz feta, 1 tsp olive oil, tomato (292 cal, 13g protein)	Cucumber and celery sticks (free, 0g protein)	4 oz pan-seared firm tofu, 1 cup roasted asparagus, 1 tsp olive oil (225 cal, 17g protein)	800 cal, 66g protein
4	4 oz plain Greek yogurt with 1/4 cup cooked oats, 1 tbsp slivered almonds, 1/2 cup mixed berries (175 cal, 14g protein)	1 hard-boiled egg with cucumber (78 cal, 7g protein)	3 oz tempeh, 2 cups mixed greens, 1 tsp olive oil, tomato, cucumber (252 cal, 17g protein)	4 oz plain Greek yogurt 0% (65 cal, 12g protein)	1 cup roasted vegetables, 1/4 cup cooked quinoa, 1 oz feta, 1 tsp olive oil (230 cal, 7g protein)	800 cal, 57g protein
5	2 large eggs with 1 cup mushrooms and 1 cup wilted spinach (215 cal, 19g protein)	4 oz plain Greek yogurt with 1/4 cup berries (85 cal, 12g protein)	1/2 cup cooked lentils, 2 cups mixed greens, 1/8 medium avocado, 1 tsp olive oil, tomato (227 cal, 11g protein)	1/2 oz pumpkin seeds (80 cal, 4g protein)	4 oz pan-seared firm tofu, 1 cup roasted bell peppers, 1 tsp olive oil (215 cal, 17g protein)	822 cal, 63g protein
6	1 cup low-fat cottage cheese with 1/2 cup mixed berries and cinnamon (205 cal, 29g protein)	1 small clementine and cucumber slices (43 cal, 1g protein)	1/2 cup chickpeas, 2 cups mixed greens, 1 tsp olive oil, tomato, cucumber (225 cal, 8g protein)	1 hard-boiled egg (70 cal, 6g protein)	3 oz tempeh, 1 cup steamed broccoli, 1 tsp olive oil (257 cal, 21g protein)	800 cal, 65g protein
7	2-egg omelette with 1 cup wilted spinach (220 cal, 14g protein)	4 oz plain Greek yogurt with 1/4 cup berries (85 cal, 12g protein)	3 oz pan-seared firm tofu, 2 cups mixed greens, 1/4 cup cooked quinoa, 1 tsp olive oil, tomato (246 cal, 16g protein)	1/2 medium apple with 1 tsp natural peanut butter (79 cal, 1.5g protein)	1/2 cup cooked lentils, 1 cup steamed cauliflower, 1 cup roasted bell peppers, 1 tsp olive oil (215 cal, 11g protein)	845 cal, 54g protein

For Type 2 Diabetics

800 Calorie Keto Meal Plan

Vegetarian

Intermittent Fasting

After the 800-Calorie Phase: The Maintenance Plan Matters More Than the Diet

The number that gets quoted from DiRECT is the 46% remission rate at 12 months. The number that doesn’t get quoted enough: at 24 months, remission rates dropped to 36%. The difference comes down to maintenance.

The structured maintenance phase that both NHS and Mosley use after the 800-calorie phase is roughly:

1,500 to 2,000 kcal per day, Mediterranean pattern
5:2 or 6:1 intermittent fasting, optional but often included
Continued check-ins for the first 6 to 12 months
Medication adjustments as weight loss is sustained

If you do the 800-calorie phase and then go back to your previous eating pattern, regain is the default outcome, not the exception. If you’re considering this protocol, build the maintenance plan first and the 800-calorie phase second.

Common Questions About the 800-Calorie Diet

Is the 800-calorie diet safe?

It can be, in specific contexts. The NHS Path to Remission program uses 800 to 900 kilocalories per day for 12 weeks under medical supervision in adults with type 2 diabetes and obesity, and outcomes are well-documented (Lancet Diabetes & Endocrinology, 2024). Self-directed 800-calorie diets without supervision carry meaningful risks including gallstones, electrolyte imbalance, muscle loss, and disordered eating patterns.

How much weight will I lose on the 800-calorie diet?

Around 1 to 1.5 kg (2 to 3 lbs) per week sustained over the 8 to 12 week protocol. The first week typically shows higher loss, but most of that is water and glycogen, not body fat. The DIAMOND study averaged 9.5 kg loss over 8 weeks; the DiRECT trial averaged 10 kg at 12 months.

How long can I follow the 800-calorie diet?

NHS guidance and the Mosley Fast 800 program both cap the 800-calorie phase at 12 weeks. Self-directed use should be limited to 1 to 2 weeks. After the intensive phase, both programs transition to a Mediterranean-style maintenance phase at 1,500 to 2,000 kcal per day.

Can I do the 800-calorie diet without a doctor?

Not recommended. The clinical evidence base comes from supervised programs with weekly check-ins, blood work, and medication adjustments. If you’re determined to try a short version on your own, limit it to 1 to 2 weeks and only if you don’t fit any of the contraindicated groups.

Is the 800-calorie diet a fad diet?

No, when applied in its clinical context (type 2 diabetes remission under supervision). Yes, when marketed as a quick-fix consumer protocol. The protocol itself has peer-reviewed evidence behind it (DiRECT, DIAMOND); the marketing of consumer versions sometimes hits fad-diet red flags. See our guide to fad diets for the full red-flag checklist.

Will I gain the weight back after?

Outcomes depend on the maintenance phase. NHS data shows about 32% sustained type 2 diabetes remission at 12 months when the protocol is followed by structured maintenance. Without a maintenance plan, regain is common and matches the metabolic adaptation pattern seen with all rapid weight loss approaches.

Can I exercise on the 800-calorie diet?

Light walking and gentle activity are fine and encouraged. Heavy resistance training or endurance training is not recommended at this calorie level. Your body will not have the substrate to recover, and muscle loss accelerates. Clinical protocols specifically de-emphasize intense exercise during the 800-calorie phase.

What’s the difference between a food-based 800-calorie plan and the NHS formula protocol?

The NHS Path to Remission uses formula meal replacements (shakes, soups, bars) because hitting full micronutrient adequacy at 800 kcal is genuinely difficult with regular food. A food-based 800-calorie plan needs careful planning to avoid deficiencies, and a registered dietitian’s input is strongly recommended.

Editorial Note and Disclaimer

This article is informational and was written by the Diets Meal Plan editorial team, drawing on guidance from the NHS Path to Remission program, the DiRECT trial (Lean et al., The Lancet, 2018), the DIAMOND study, and the 2024 Lancet Diabetes & Endocrinology evaluation of the NHS program. It is not medical advice and is not a substitute for evaluation by a qualified clinician. Very Low Calorie Diets carry real risks and should be undertaken with medical supervision, especially if you have diabetes, blood pressure issues, kidney concerns, or are on prescription medications.

See our editorial policy for how we research and update health content.