Food and Human Health : General Awareness of Balanced and Unbalanced Food
Food has been a basic part of our existence. By knowing the food composition , the nutritional content of food is known. Intake of food ensures growth in children and youth, maintains good health throughout life, meets special needs of pregnancy and lactation and for recovery from illness. A large part of our food heritage is scientifically beneficial and needs to be retained, some aspects may need to be modified in view of changes in our lifestyles.
Nutrients are components of foods needed for body in adequate amounts for proper growth, reproduction and leading normal life. The science of nutrition deals with what nutrients we need, in what quantity, how to get them and how the body utilizes them. Adequate, optimum and good nutrition – indicates the right amount and proportion of nutrients for proper utilization for achieving highest level of physical and mental health.
Nutrients that we obtain through food have vital effects on physical growth and development, maintenance of normal body function, physical activity and health. Nutritious food is, thus needed to sustain life and activity. Our diet must provide all essential nutrients in the required amounts. Requirements of essential nutrients vary with age, gender, physiological status and physical activity. Dietary intakes lower or higher than the body requirements can lead to under nutrition (deficiency diseases) or over nutrition (diseases of affluence) respectively. Eating too little food during certain significant periods of life such as infancy, childhood, adolescence, pregnancy and lactation and eating too much at any age can lead to harmful consequences. An adequate diet, providing all nutrients, is needed throughout our lives. The nutrients must be obtained through a judicious choice and combination of a variety of foodstuffs from different food groups.
Carbohydrates, fats and proteins are macronutrients, which are needed in large amounts. Vitamins and minerals constitute the micronutrients and are required in small amounts. These nutrients are necessary for physiological and biochemical processes by which the human body acquires, assimilates and utilizes food to maintain health and activity.
A balanced diet is one which provides all the nutrients in required amounts and proper proportions. It can easily be achieved through a blend of the four basic food groups. The quantities of foods needed to meet the nutrient requirements vary with age, gender, physiological status and physical activity. A balanced diet should provide around 50-60% of total calories from carbohydrates, preferably from complex carbohydrates, about 10-15% from proteins and 20-30% from both visible and invisible fat.
In addition, a balanced diet should provide other non-nutrients such as dietary fibre, antioxidants and phytochemicals which bestow positive health benefits. Antioxidants such as vitamins C and E, beta-carotene, riboflavin and selenium protect the human body from free radical damage. Other phytochemicals such as polyphenols, flavones, etc., also afford protection against oxidant damage. Spices like turmeric, ginger, garlic, cumin and cloves are rich in antioxidants. Balanced Diet for Adults – Sedentary/Moderate/Heavy Activity is given in annexure 2 and figures 3 & 4. Also, sample menu plans for sedentary adult man and woman are given in annexure 2a and 2b respectively.
Requirements are the quantities of nutrients that healthy individuals must obtain from food to meet their physiological needs. The recommended dietary allowances (RDAs) are estimates of nutrients to be consumed daily to ensure the requirements of all individuals in a given population. The recommended level depends upon the bioavailability of nutrients from a given diet. The term bioavailability indicates what is absorbed and utilized by the body. In addition, RDA includes a margin of safety, to cover variation between individuals, dietary traditions and practices. The RDAs are suggested for physiological groups such as infants, pre-schoolers, children, adolescents, pregnant women, lactating mothers, and adult men and women, taking into account their physical activity. In fact, RDAs are suggested averages/day. However, in practice, fluctuations in intake may occur depending on the food availability and demands of the body. But, the average requirements need to be satisfied over a period of time.
An imbalanced diet consists of either an excess or inadequate intake of any dietary component. This generally pertains to the three macronutrients: carbohydrates, protein and fat. For example, too much fat and protein with insufficient carbohydrates results in an imbalanced diet. Too many calories or too few calories is another type of imbalance. While there is no such thing as a perfect diet, striving to maintain balance in your diet can help prevent nutritional deficiencies and unwanted weight gain.
The recommended intake for carbohydrates is 45 to 65 percent of your daily calories. But don’t rely on just any carbohydrates to fulfill that number. Choose whole-food, nutrient-dense sources such as brown rice, oats, sweet potatoes, fruits and whole-grain breads. Limit highly processed and refined carbohydrates like white bread, white pasta, white rice and white sugar. Ensuring that you consume adequate amounts as well as a wide variety of carbohydrates from fruits, vegetables, whole grains and beans means that your fiber, vitamin and mineral intakes will be balanced too.
Ten to 35 percent of your calories should come from protein. Protein is found in many foods in small amounts but is most concentrated in meats, fish, eggs, dairy, nuts and beans and lentils. Go lean and light when eating meats and dairy products. The protein in plant foods adds up too. As a general rule, if you are eating enough calories from whole-food sources, then you are getting enough protein. Consuming large portions of animal products is the main contributor to excessive protein intake. Keep meat portions to about 2 to 3 ounces per meal.
The recommended number of daily calories supplied by fat is 20 to 35 percent. As with carbohydrates and protein sources, a balanced diet requires the right types of fats. Avoid any product made with trans fats, or partially hydrogenated oils. Choose more plant-based fats such as nuts, seeds and avocado and fewer animal fats like butter, full-fat cheese and fatty meats. Watch out for fried foods as they are high in unhealthy fats.