We all want to eat food that is nutritious. But how exactly do we define the nutritional value of a food? The simplest way around this problem is to first identify what is good for our health and what is bad. Nutrients such as vitamins, minerals, essential amino acids, and essential fatty acids help promote good health. On the other hand, excess calorie intake has been shown to be not so good for our health as it leads to obesity, diabetes, and heart-related problems. So, it makes sense to define the nutritional value of a product using the formula:
Nutritional Value (NV) = Nutrients/Calories
Basically, NV is a number of nutrients contained in a food for each calorie it delivers. So, where exactly should different food items be placed on the nutrition list?
Why do we care?
Modern lifestyle has reduced the amount of physical activity performed by an average individual. This lifestyle change, combined with the easy availability of calorie dense food, has led to the widespread prevalence of obesity and associated diseases. Realising this, people have started cutting calories by reducing food intake. The potential side-effect of this behavioural change is that we are also getting less and less of life sustaining nutrients such as vitamins and minerals. For instance, one might decide to limit daily calorie intake to 1600 kcal to reduce weight. This calorie target can be achieved by drinking just the amount of cola equivalent to these many calories. But this way you will be losing on other essential nutrients and your health will deteriorate over time. Instead, you should switch to a diet that contains low calories but sufficient amounts of other nutrients. Solution: eat foods that are placed high on the nutrition list.
Nutritional Value of common food items
Each 500ml bottle of Coca-Cola has around 186 Kcal and virtually zero nutrition; hence, its nutritional value is nil. Sweetened nimbu-pani fares slightly better than cola because nimbu-pani at least contains vitamin-C, however, this home-made beverage still has a high concentration of sucrose and calories. It still fares pretty low on our list. Similarly, potato-chips, Maggi, beer, and biscuits are all at the bottom of the list. For example, 100 grams of lays has in excess of 500 kcal with very little nutrition. On the other hand, spinach is a nutrient dense food. A 100g serving of spinach contains just 23 calories, but tens of other micronutrients such as vitamin-A, vitamin-C, iron, vitamin-B6, magnesium, phosphorous, folate and so on. Similarly, carrots, onions, cabbage, broccoli etc. are the kinds of food you should be eating if you are on a low-calorie diet. The importance of protein cannot be overstated and make sure to include a good portion of protein rich foods such as lentils (dal), milk, lean meat (poultry and fish), and eggs in your diet.
Not only do different foods have different nutritional value, different parts of the same fruit or vegetable may pack nutrients in different concentrations. For example, the peel of an apple has more micronutrients than rest of the apple combined and significantly less number of calories. Similarly, in a potato, the part that we eat (the pulp) is just pure starch and the part that we throw away (the skin) has most of the nutrients packed.
Long Story Short
If your goal is to lose weight or maintain weight, and you are limiting your calorie consumption to achieve it, make sure that you are not reducing your intake of other nutrients. To achieve this, you should be eating foods with high nutritional value, which is a measure of nutrients contained per unit calorie of food.