Nutrition Diet: What is the one food that has everything you need?

November 2, 2025 •

5 min read

According to the World Health Organization, a healthy diet is composed of a combination of different foods, not just one. The idea that there might be a single, ultimate 'perfect food'—what is the one food that has everything you need?—is a persistent myth in nutrition that is important to debunk for overall health.

Quick Summary

This article debunks the myth of a single nutritionally complete food, explaining why humans require a varied diet. It highlights the most nutrient-dense foods, contrasts a varied versus single-food diet, and clarifies the potential health risks of eating only one type of food.

Key Points

No Single Perfect Food: There is no one food that contains all the nutrients an adult human needs for optimal long-term health, as our bodies evolved to thrive on variety.
Breast Milk for Infants: Human breast milk is considered a complete food for infants in their first months, but it is not a viable sole food source for adults and lacks some nutrients.
Nutrient-Dense Foods: Some foods, like eggs, liver, and salmon, are incredibly rich in a wide range of nutrients but should be part of a broader diet due to their limitations.
Danger of Mono-Diets: Restrictive diets based on a single food item can lead to severe nutrient deficiencies, muscle loss, digestive problems, and metabolic slowdown.
Variety is the Key: A balanced, varied diet incorporating foods from all major food groups (fruits, vegetables, protein, etc.) is the best approach to ensuring comprehensive nutrition.
Health Risks of Excess: Even highly nutritious foods like liver can be harmful in excess, as high concentrations of certain vitamins (like Vitamin A) can become toxic.

The Myth of a Single 'Perfect Food'

For humans, the concept of a single 'perfect food' is a myth. Unlike some animals that have evolved to live off a single, specific food source, humans are omnivores who require a wide variety of nutrients from diverse foods. Our bodies are complex and need a synergistic mix of macronutrients (proteins, fats, carbohydrates), micronutrients (vitamins, minerals), and other compounds like fiber and antioxidants, which are not all present in the right proportions in any one food.

Even foods often cited as nutritionally complete, such as eggs, have limitations. While eggs are a powerhouse of nutrients, they famously lack Vitamin C. Restrictive single-food or 'mono' diets can be dangerous, leading to severe nutritional deficiencies over time. For adults, relying on one food can cause issues ranging from anemia and muscle loss to organ damage and mental health problems.

Nature's Closest Contenders

While no single food is complete for adult human nutrition, some are exceptionally nutrient-dense. These foods are excellent additions to a balanced diet but cannot serve as the sole source of sustenance.

Human Breast Milk (for infants): For a specific period of life, human breast milk is the gold standard for infant nutrition. It is a complex, dynamic fluid that contains the perfect balance of macronutrients, micronutrients, and bioactive factors to support a newborn's growth and immune system. However, it is not designed to be the sole food source for adults and even requires supplementation for infants in some nutrients, such as Vitamin D and K.
Eggs: Often called 'nature's multivitamin,' eggs are a powerhouse of nutrition. One large egg contains high-quality protein with all nine essential amino acids, along with important nutrients like Vitamin B12, Vitamin D, choline, selenium, and antioxidants lutein and zeaxanthin. The yolk contains most of the vitamins and healthy fats, while the white is primarily protein. Their high satiety value can also help with weight management.
Liver (Organ Meat): Animal liver is among the most nutrient-dense foods available, rich in Vitamin A, B vitamins (especially B12), iron, copper, selenium, and high-quality protein. However, it is not a complete food and contains very high levels of certain nutrients. Excessive consumption can lead to toxicities, particularly Vitamin A and copper. For this reason, it should be eaten in moderation.
Salmon and Sardines: Oily fish are excellent sources of heart-healthy omega-3 fatty acids, which are essential nutrients. They also contain high-quality protein and a range of vitamins and minerals. Sardines can be eaten whole, providing nutrients from bones and organs.
Leafy Greens: Vegetables like kale are packed with vitamins (C, A, K), minerals, fiber, and antioxidants. While low in calories, they are an essential part of a balanced diet for their micronutrient content.

The Problem with Restrictive Single-Food Diets

Following a diet that restricts you to just one food is not only unsustainable but also dangerous. It can lead to a host of health problems, as the body is denied the wide range of nutrients it needs to function properly. The long-term negative effects can be severe, demonstrating why variety is a cornerstone of good nutrition.

Nutrient Deficiencies: Even the most nutrient-dense foods have gaps. For instance, meat lacks Vitamin C, while plant-based foods lack Vitamin B12. A mono-diet inevitably leads to multiple deficiencies over time.
Muscle Loss: Extreme calorie restriction and a lack of balanced protein intake from a single-food diet can cause the body to break down muscle tissue for energy, negatively affecting metabolism and strength.
Digestive Issues: A single-food diet can disrupt the delicate balance of the gut microbiome, leading to constipation, diarrhea, and other digestive problems due to lack of fiber or other compounds.
Mental and Emotional Health: The stress and restrictiveness of a mono-diet can cause irritability, fatigue, and can even trigger disordered eating habits. The brain needs a variety of nutrients to function properly, and denying it can lead to 'brain fog'.

Comparison: Single-Food vs. Varied Diet


Aspect	Single-Food Diet	Varied Diet (Balanced)
Nutrient Profile	Extremely limited, with significant gaps in essential vitamins, minerals, and macronutrients.	Provides a broad spectrum of nutrients from different food groups, ensuring all essential needs are met.
Risk of Deficiency	Very high risk of developing severe deficiencies over time, as no single food contains all necessary nutrients.	Very low risk of deficiency, as a variety of foods fills in nutritional gaps.
Sustainability	Not sustainable for long-term health; can lead to burnout, cravings, and poor health outcomes.	Highly sustainable and enjoyable, fostering a healthy relationship with food.
Health Outcomes	Can cause malnutrition, muscle loss, organ damage, and metabolic slowdown, despite potential initial weight loss.	Promotes optimal physical and mental health, reduces the risk of chronic diseases like diabetes and heart disease.
Satiety and Energy	Can cause intense cravings and fatigue, as the body is not getting balanced energy from diverse sources.	Provides long-lasting energy and balanced blood sugar levels, reducing unhealthy snacking.

The Importance of Variety and Balance

For optimal health, the best approach is to embrace the variety that nature offers. Humans evolved to get nutrients from a diverse range of sources. A balanced diet, as recommended by health organizations like the World Health Organization and the American Heart Association, emphasizes consuming a variety of foods from all food groups. This includes plenty of fruits, vegetables, whole grains, lean proteins, healthy fats, and low-fat dairy.

By building meals from different food groups, you ensure a comprehensive intake of all essential nutrients, providing the body with everything it needs to function properly. While some foods are more nutritionally potent than others, the real power lies in their combination, not in the solitary consumption of any one item. For example, pairing nutrient-dense liver with a Vitamin C-rich side like broccoli can help with iron absorption, demonstrating how different foods work together to improve overall nutrition.

Conclusion

In the realm of nutrition, the quest for a single 'perfect food' is a fool's errand. While certain foods like eggs, liver, and oily fish are exceptional for their nutrient density, they each have their limitations and should be part of a larger, varied diet. For adults, relying on one food is not only unsustainable but also dangerous, as it risks severe nutrient deficiencies. The human body is designed to thrive on a diverse diet, and embracing variety from all food groups is the most effective and safest way to ensure comprehensive nutrition and long-term health.

For more information on dietary needs and food groups, consult the dietary guidelines from reputable health organizations.

Frequently Asked Questions

No single food contains every nutrient required for adult human health. The idea of a nutritionally complete single food is a myth. For optimal health, humans need to consume a varied diet from different food groups to obtain all necessary vitamins, minerals, and macronutrients.

While eggs are exceptionally nutritious and are sometimes called 'nature's multivitamin', they are not a perfect, complete food. They contain high-quality protein and many essential vitamins and minerals but lack Vitamin C and other compounds found in fruits and vegetables.

Yes, for the first few months of life, human breast milk is the ideal and complete food for infants, providing all the necessary energy, nutrients, and immune-protective factors. However, as the infant grows, complementary foods are introduced, and it is not a complete food source for adults.

No, a mono-diet is not a healthy or sustainable weight loss method. It can lead to severe nutrient deficiencies, fatigue, and muscle loss. While it might cause short-term weight loss, this is often unsustainable, and the weight is regained once normal eating resumes.

A varied diet is essential for adults because different foods provide different nutrients. By eating a wide variety of foods from different groups, you ensure that your body receives the full spectrum of vitamins, minerals, fiber, and other compounds needed for all bodily functions.

No, organ meats are extremely nutrient-dense but are not a complete food. Liver, for example, is rich in Vitamin A and B12 but should be eaten in moderation to avoid toxicities, especially from excessive Vitamin A and copper intake.

If you don't eat a variety of foods, you risk developing nutrient deficiencies, which can cause serious health issues like anemia, osteoporosis, and malnutrition. It can also negatively impact your energy levels, digestion, and mental health.