A Healthy Human Diet

A balanced diet is an important part of maintaining overall health and well-being. It involves consuming a variety of nutrients in the right amounts to support the body’s needs.

All living organisms need nutrients to stay alive and healthy. There are many different types of nutrients, but they all fall into seven main categories:

  • Carbohydrates – A primary source of energy for the body. They are found in bread, pasta, rice, fruits, and vegetables
  • Proteins – Necessary for the growth, repair, and maintenance of tissues. They are found in foods such as meat, eggs and legumes (e.g. beans, peas and peanuts).
  • Lipids (fats and oils) – A rich source of energy. They are found in sources such as butter, nuts and seeds.
  • Minerals – Essential for various bodily functions, including maintaining strong bones and teeth, regulating heartbeat, and supporting the immune system. There are 16 essential minerals and they are found in sources such as dairy foods, meat, and green leafy vegetables.
  • Vitamins – Essential for maintaining good health and are found in a variety of fruits and vegetables.
  • Water – Essential for maintaining proper hydration and supporting various bodily functions. About 70% of the human body is made up of water. Since we lose water through sweat, urine and exhalation, it’s essential to replenish lost fluids. The exact amount of water you need can vary based on factors like age, gender, weight and level of physical activity.

A vibrant assortment of fresh and healthy foods spread out on a textured surface. The selection includes a piece of raw meat, lush spinach leaves, strawberries, raspberries, blueberries, an avocado, broccoli, a bowl of nuts and seeds, and a bottle of olive oil, all artistically arranged to showcase their freshness and nutritional value.


Although fibre cannot be absorbed by the body, it is an important part of a healthy diet. Fibre passes through the digestive system largely intact, providing bulk and helping to move waste through the intestines.

  • Foods that are high in fibre can help reduce constipation

Fibre is found in plant-based foods like fruits, vegetables, grains and legumes.

Energy Calculations

A balanced diet is essential for optimal health and involves eating a variety of foods that provide the body with the nutrients it needs to function properly.

The recommended dietary allowance (RDA) is a set of guidelines issued by the government. It provides information on the right amount of each nutrient that should be consumed daily to meet the needs of 97% to 98% of the population.

According to the NHS guide for maintaining a healthy weight:

  • The average man needs about 2,500 kcal (10,500 kJ) per day
  • The average woman requires 2,000 kcal (8,400 kJ) per day

However, keep in mind that the RDA is a general guideline; individual nutrient needs can vary based on factors like age, gender and physical activity level.

The government has introduced a ‘traffic light system’ to indicate whether a food item has high, medium,or low levels of fat, saturated fat, sugars, and salt. For example:

A food nutrition label showing various components and their levels. The label displays: 'Energy' at 1046kJ and 250kcal, making up 13% of the daily intake; 'Fat' at 3.0g marked as 'LOW' and constituting 4%; 'Saturates' at 1.3g also marked 'LOW' and making up 7%; 'Sugars' at 34g marked as 'HIGH' and contributing to 38%; and 'Salt' at 0.9g labelled 'MED' for medium and amounting to 15% of daily intake. Each component is colour-coded, with green for low, amber for medium, and red for high.

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