What Will Happen if You Only Eat Fruits and Vegetables in Your Diet?

December 24, 2025 •

4 min read

While fruits and vegetables are packed with vitamins and minerals, a restrictive diet consisting of only these foods is considered unhealthy and dangerous by nutrition experts. Explore what will happen if you only eat fruits and vegetables in your diet, and why relying solely on them can lead to severe health issues.

Quick Summary

Eating exclusively fruits and vegetables can lead to critical nutrient deficiencies, insufficient calories, and other health complications. This restrictive diet is not recommended for long-term health and is not considered a balanced eating plan.

Key Points

Nutrient Deficiencies: An exclusively fruit and vegetable diet will cause severe deficiencies in protein, vitamin B12, iron, calcium, and essential fatty acids, among others.
Insufficient Calories: These foods are generally low in calories, making it very difficult to meet daily energy needs, leading to fatigue and muscle loss.
Digestive Discomfort: A sudden, high-fiber diet can cause gas, bloating, and other intestinal distress, especially during the initial transition period.
Long-Term Health Risks: Sustaining this restrictive diet can lead to serious conditions like anemia, osteoporosis, weakened immunity, and neurological problems.
Balance is Key: Incorporating fruits and vegetables into a balanced diet alongside lean proteins, healthy fats, and whole grains is the correct and sustainable approach to good health.
Not for Vulnerable Groups: This diet is particularly dangerous and not recommended for children, pregnant women, or those with existing health issues.

The Initial (Short-Term) Effects

For a short period, such as a few days, transitioning to a diet of only fruits and vegetables might cause a few noticeable changes, some of which people perceive as positive. The high water and fiber content can lead to a feeling of fullness, potentially resulting in short-term weight loss. However, this initial weight reduction is often temporary and primarily due to water loss and decreased calorie intake, not sustainable fat loss. You may also experience a reduction in inflammation, as plant-based foods are naturally rich in antioxidants and fiber, which help fight inflammation. C-reactive protein (CRP), a marker for inflammation, often decreases in individuals adopting a plant-based diet.

Digestive System Changes

An abrupt increase in fiber from fruits and vegetables can shock the digestive system. Many people experience uncomfortable gas, bloating, and potential diarrhea or constipation. For individuals with irritable bowel syndrome (IBS), high FODMAP fruits and vegetables can significantly worsen symptoms. Over time, the gut can adapt, but this transition period can be unpleasant. While a high-fiber diet is generally healthy, balance and gradual introduction are key.

The Serious Risks of Long-Term Restriction

Extending an all-fruit-and-vegetable diet beyond a few days or weeks poses significant health risks due to nutritional gaps. While nutritious, these foods are not nutritionally complete.

Severe Nutrient Deficiencies

Over time, this diet will inevitably lead to multiple critical nutrient deficiencies because fruits and vegetables lack key macronutrients and micronutrients found in other food groups.

Protein Deficiency: Protein is essential for building and repairing muscle, tissue, and hormones. Fruits and vegetables contain minimal protein, and without adequate intake, the body begins breaking down muscle tissue to supply amino acids, leading to muscle mass loss and weakness.
Essential Fatty Acids (Omega-3s): Fruits and vegetables are not significant sources of omega-3s like EPA and DHA, which are crucial for brain function, hormone regulation, and reducing inflammation. Prolonged deficiency can impact mood, cognitive function, and cardiovascular health.
Vitamin B12: This vitamin is almost exclusively found in animal products and is vital for nerve function and red blood cell production. Deficiency can lead to anemia, fatigue, and severe, irreversible neurological damage. Vegans must supplement, and a fruit-and-vegetable-only diet provides no B12 whatsoever.
Iron: Plant-based (non-heme) iron is poorly absorbed by the body compared to heme iron from animal sources. Many leafy greens contain phytates that inhibit iron absorption even further. Long-term inadequacy can cause anemia, fatigue, and cognitive impairment.
Calcium and Vitamin D: Both are critical for bone health, and a diet lacking dairy and other fortified foods can lead to bone mineral density loss and an increased risk of fractures and osteoporosis.
Zinc: Important for immune function and wound healing, zinc's bioavailability from plant sources is limited, increasing the risk of deficiency.

Dangers for Specific Populations

Vulnerable populations face even greater dangers. For children, a fruit-and-vegetable-only diet severely hinders growth and development. Pregnant and breastfeeding women risk severe deficiencies that can harm both themselves and their baby, with documented cases of tragic outcomes. It is essential for these groups to consume a complete, balanced diet.

Other Negative Health Consequences

Beyond nutrient shortfalls, this diet can cause other issues:

Tooth Decay: The high sugar content and acidity of fruits, especially when consumed in large quantities, can erode tooth enamel over time, increasing the risk of dental cavities and decay.
Metabolic Slowdown: A severely calorie-restricted diet can put the body into "starvation mode," where metabolism slows down to conserve energy. This can make long-term weight loss more difficult and cause fatigue and weakness.
Mental Health Impact: While initially feeling lighter, long-term restriction can lead to mood disturbances, fatigue, and an unhealthy relationship with food. Low levels of key nutrients like B12 and omega-3s are directly linked to mental health issues.

A Balanced Approach: Incorporating All Food Groups

Experts agree that a diet rich in fruits and vegetables is beneficial, but only when integrated into a complete, balanced eating plan. Incorporating healthy sources of protein, fats, and other nutrients is non-negotiable for long-term health.

Comparison: Unbalanced vs. Balanced Diet


Feature	Fruits & Vegetables Only (Unbalanced)	Fruits & Vegetables as Part of a Balanced Diet
Macronutrients	Deficient in protein and fats.	Contains adequate protein, fat, and carbohydrates.
Micronutrients	Deficient in B12, calcium, vitamin D, iron, zinc, etc.	Provides a full spectrum of vitamins and minerals.
Energy Levels	Significant drop in energy, fatigue.	Sustained energy throughout the day.
Muscle Mass	Leads to loss of muscle mass.	Maintains and builds muscle mass.
Dental Health	High risk of enamel erosion and tooth decay.	Lower risk due to less consistent acid/sugar exposure.
Digestion	Initial bloating, gas, discomfort.	Smooth digestion with adequate fiber.
Sustainability	Not sustainable long-term; health risks.	Sustainable, healthy, and long-term friendly.

Conclusion: Prioritize Balance, Not Restriction

While the goal of a healthier diet is commendable, the idea of eating only fruits and vegetables is a flawed and dangerous approach. The initial 'detox' feeling and weight loss are not indicative of long-term wellness and come at the cost of severe nutritional deficiencies and health complications. Instead of extreme restriction, the key to lasting health is a balanced diet that includes a wide variety of foods from all major food groups—incorporating fruits and vegetables alongside lean proteins, healthy fats, and whole grains. For authoritative guidance on balanced nutrition, consult resources like the CDC's healthy eating guidelines. A short-term fast of 2-3 days might be okay for some, but a fruits and vegetables-only diet is never the answer for sustained well-being. Always consult a healthcare provider or registered dietitian before making drastic dietary changes.

Frequently Asked Questions

No, fruits and vegetables are not significant sources of protein. A diet consisting only of these foods will not provide enough protein for muscle repair and maintenance, leading to muscle loss and weakness.

A very short-term, 2-3 day cleanse might not be harmful for a healthy adult, but it is not recommended as a long-term solution. It will mostly result in water weight loss. You should always consult a doctor before making major dietary changes, and longer periods are dangerous.

Yes, many people experience gas, bloating, and changes in bowel movements when they first increase their fiber intake dramatically. This is a common side effect as your body adjusts to the high volume of fiber.

The most critical deficiencies include vitamin B12 (found almost exclusively in animal products), protein, essential fatty acids, and minerals like calcium, iron, and zinc. These can have serious, long-term health consequences.

While the high fiber and antioxidant content can reduce inflammation and cholesterol initially, these benefits are outweighed by the long-term nutritional deficiencies and health risks associated with the restrictive nature of the diet.

The high acidity and sugar content in many fruits can erode tooth enamel over time, increasing your risk of dental problems like cavities and decay, especially when consumed in large quantities.

A much healthier approach is to incorporate a variety of colorful fruits and vegetables into a balanced diet that also includes whole grains, legumes, nuts, seeds, and healthy protein sources. This provides a wider range of nutrients necessary for good health.