What Is a Very-Low Calorie Diet?

A very low-calorie diet typically involves consuming 800 calories or fewer per day. Originally developed in the 1970s for patients with a body mass index (BMI) of 30 or higher, VLCDs aim to achieve rapid weight loss under medical supervision.

These diets often replace regular meals with specially formulated products like shakes, soups, or bars to ensure nutritional adequacy despite the low calorie intake.

Is a Very Low-Calorie Diet Safe?

VLCDs are not recommended for most individuals unless under strict medical supervision. They are primarily designed for those with significant obesity-related health issues. Potential side effects include fatigue, constipation, nausea, and diarrhea.

More severe risks encompass gallstones, muscle loss, and nutritional deficiencies. It's imperative to consult with healthcare professionals before considering such a diet.

Example Very Low-Calorie Diet Meal Plan

Below is a sample 3-day VLCD meal plan. Please note that individual needs vary, and it's essential to consult with a dietitian or your primary healthcare professional before starting any VLCD.

Day 1

Breakfast: 1 Boiled Egg And 1 Slice Of Whole-Grain Toast With Coffee Or Black Tea

This breakfast keeps it simple and protein-packed. A boiled egg offers a steady source of energy and essential amino acids, while the whole-grain toast adds fiber to help you feel fuller longer.

Brewed black coffee or tea gives a mild energy boost without adding calories. Quick to make and easy to enjoy.

Snack: 1 Medium Apple

Apples are high in water and fiber, which helps with satiety. One medium apple is just enough to keep hunger at bay between meals. It’s portable, affordable, and needs no prep, making it a solid mid-morning snack.

Lunch: Grilled Chicken Salad

Grilled chicken is lean and rich in protein, making it a VLCD staple. Paired with mixed greens and a light vinaigrette, this meal is low in calories but full of volume and flavor. Assemble it fresh with your favorite leafy greens for the best crunch.

Snack: Low-Fat Yogurt (Plain)

Plain low-fat yogurt offers protein and gut-friendly probiotics. It’s a satisfying, creamy snack that doesn’t come with added sugar. Stick to around half a cup and top it with a dash of cinnamon if you want extra flavor.

Dinner: Steamed Fish With Steamed Vegetables

Steamed fish, such as cod or tilapia, is a light yet nutrient-dense protein choice. Add a side of steamed non-starchy vegetables—think zucchini, broccoli, or cauliflower. It’s an easy, no-fuss dinner that fills you up without overdoing it on calories.

Day 2

Breakfast: Oatmeal Made With Water, Topped With Berries

Oatmeal is warm, filling, and high in soluble fiber. Making it with water instead of milk keeps the calorie count low. A few fresh or frozen berries on top add natural sweetness and antioxidants. It’s comforting without being heavy.

Snack: Carrot Sticks

Crunchy, naturally sweet, and packed with beta-carotene, carrot sticks are a satisfying, low-calorie snack. Slice them fresh in the morning and store them in water to keep them crisp all day.

Lunch: Turkey Sandwich With Lettuce On Whole-Grain Bread

Lean turkey breast is high in protein and low in fat, making it a great lunch option. Use one slice of whole-grain bread folded with lettuce for crunch and fiber. Skip the cheese and mayo to keep it VLCD-friendly.

Snack: A Small Handful Of Almonds

Almonds are calorie-dense, so portion control matters. A small handful (about 10–12) provides healthy fats and a bit of protein, which helps bridge the gap between meals. They're convenient and shelf-stable.

Dinner: Stir-Fried Tofu With Mixed Vegetables

Tofu is a plant-based protein that absorbs flavors beautifully. Stir-frying it with non-starchy vegetables like bok choy, bell peppers, and mushrooms keeps it flavorful but light. Use a splash of low-sodium soy sauce or vinegar for seasoning.

Day 3

Breakfast: Banana And Spinach Smoothie With Low-Fat Milk

Smoothies are a great way to sneak in nutrients. Low-fat milk offers protein and calcium, banana gives natural sweetness and creaminess, and spinach blends in seamlessly for an iron boost. It’s quick, cool, and energizing.

Snack: Celery Sticks With Hummus

Celery is high in water and crunch, while hummus brings a creamy texture and a bit of protein and fiber. A couple of tablespoons go a long way. This combo adds variety and keeps things interesting.

Lunch: Lentil Soup With A Side Salad

Lentils are rich in protein and fiber, making them an excellent choice on a VLCD. A bowl of homemade or low-sodium lentil soup is warm and filling. Pair it with a simple salad of leafy greens and lemon juice for a refreshing contrast.

Snack: A Small Orange

Oranges are naturally sweet and packed with vitamin C. One small orange offers hydration and a burst of flavor without tipping the calorie scale. It’s also easy to carry and peel.

Dinner: Grilled Shrimp With Quinoa And Steamed Broccoli

Shrimp is a low-fat, high-protein seafood option. Grill it with a touch of garlic or lemon for flavor. Serve alongside a small portion of quinoa for texture and fiber, plus steamed broccoli to round out the plate with color and nutrients. It's light, satisfying, and dinner-ready in under 20 minutes.

Foods You Can Eat On A Very Low-Calorie Diet

When following a VLCD, focus on nutrient-dense, low-calorie foods:

• Lean proteins: chicken breast, turkey, tofu, legumes

• Non-starchy vegetables: spinach, broccoli, cauliflower, zucchini

• Fruits: berries, apples, oranges (in moderation)

• Whole grains: quinoa, brown rice (limited portions)

• Low-fat dairy: yogurt, skim milk

• Healthy fats: olive oil, avocados (used sparingly)

Foods To Avoid On A Very-Low Calorie Diet

Certain foods can hinder progress on a VLCD:

• Sugary snacks and desserts

• Fried and fast foods

• Processed meats and high-fat cuts

• Sugary beverages and alcohol

• High-calorie condiments and sauces

Risks Of A Very Low-Calorie Diet

Very low-calorie diet plans, such as a no-carb diet plan for 2 weeks, may sound like a quick fix, but they come with significant risks, especially when not medically supervised. From our research and clinical experience at Berry Street, here are the top concerns we urge anyone considering a VLCD to be aware of:

Nutritional Deficiencies

When calorie intake dips below 800 calories per day, it becomes extremely difficult to meet the body’s daily nutrient needs. Essential vitamins and minerals—like vitamin B12, iron, calcium, potassium, and magnesium—are often lacking in such restrictive diets.

This can lead to fatigue, dizziness, weakened immunity, and long-term complications like anemia or bone loss. Even if weight loss occurs, poor nutrient intake can compromise overall health, energy, and well-being.

Gallstones

Rapid weight loss significantly increases the risk of developing gallstones—hard deposits that form in the gallbladder. When the body metabolizes fat quickly, it releases extra cholesterol into the bile, which can lead to stone formation.

Gallstones can cause severe abdominal pain, nausea, and digestive issues. In many cases, they may require medical treatment or even surgery. VLCDs, especially when unsupervised, heighten this risk dramatically.

Muscle Loss

The body doesn't just burn fat on a very low-calorie diet—it can also turn to muscle for fuel. Without enough dietary protein and energy, muscle tissue begins to break down.

This loss not only weakens physical strength but also slows metabolism, making it harder to keep the weight off in the long run. Muscle mass plays a key role in mobility, balance, and overall metabolic health. Losing it can affect more than just aesthetics.

Metabolic Slowdown

Cutting calories drastically may prompt the body to enter a "conservation mode," slowing down its metabolic rate. This makes it more difficult to lose weight over time and easier to regain it after the diet ends.

The body adjusts by burning fewer calories at rest, which can lead to frustration and rebound weight gain. From our experience, a slower metabolism is one of the biggest obstacles to maintaining weight loss after a VLCD ends.

Psychological Effects

Extreme dieting, whether you’re following a very low-calorie diet or a metabolic confusion meal plan, can have a powerful impact on mental health. Mood swings, irritability, fatigue, and preoccupation with food are common. For some, it may trigger or worsen disordered eating patterns.

Over time, this can lead to a strained relationship with food, body image issues, or eating disorders such as anorexia nervosa. If you find yourself feeling anxious around food, obsessively counting calories, or experiencing guilt after eating, it’s important to seek support. 

We strongly encourage connecting with a Registered Anorexia Dietitian to talk through these concerns and get tailored, compassionate guidance. It’s okay to ask for help, and it often makes all the difference.

Fatigue And Low Energy

On a very low-calorie diet, it’s common to feel constantly tired. This isn’t just mild sluggishness—it can become profound fatigue that affects your ability to concentrate, work, or exercise. The body lacks sufficient fuel to support daily activities, let alone physical exertion. 

We’ve seen how this fatigue can spill over into mood, motivation, and quality of life. It becomes harder to maintain an active lifestyle, which is critical for long-term weight management and health.

Heart Health Complications

Extreme calorie restriction can negatively impact heart function. Electrolyte imbalances—especially low levels of potassium, calcium, and magnesium—can disrupt normal heart rhythms.

In some cases, this can lead to arrhythmias, fainting, or even cardiac arrest. From our research, these complications are rare but serious, particularly in people who attempt VLCDs without medical oversight. The heart is a muscle, and like any other muscle, it weakens when the body is deprived of essential nutrients.

Compromised Immune Function

When nutrient intake is too low, the immune system takes a hit. Vitamins A, C, E, and zinc are crucial for immune defense, and they’re often insufficient on a VLCD. This can leave the body more vulnerable to infections and slow the healing process.

In the short term, you might catch colds more often. Over time, the immune suppression can become more severe. This is one reason we strongly caution against using a VLCD without ongoing input from a Registered Dietitian. Your body needs to be nourished, not just lighter.

What's The Best Way To Actually Lose Weight?

The best way to actually lose weight isn’t about drastic cuts or punishing restrictions—it’s about building habits that you can maintain long-term. Sustainable weight loss comes from a combination of balanced nutrition, consistent physical activity, and mindful behavior change. 

Instead of slashing calories down to unsustainable levels, aim for a moderate deficit that allows your body to burn fat while still getting the nutrients it needs.

This approach supports energy, mood, and overall health. One way to go about this is to follow a macro-counting meal plan and do macro meal prep alongside it. From our experience at Berry Street, the most lasting results come from plans that feel realistic, not rigid.

If you’re ready to take a more effective and personalized approach, connect with a Registered Weight Loss Dietitian through Berry Street. We’ll work with you to create a custom 7-day meal plan that fits your goals, lifestyle, and food preferences—without the extremes.

Conclusion

While VLCDs can offer rapid weight loss under medical supervision, they come with significant risks and are not suitable for everyone. Prioritizing a balanced, sustainable approach to weight loss is key.

For personalized guidance, consider connecting with a Registered Dietitian through Berry Street to embark on a healthier, more effective weight loss journey.