Of the lifestyle factors that affect your health, nutrition is probably the most important. This is so because basically what you eat is the raw material for the maintenance and repair of your body systems. If it’s wrong, you are set for a lifetime of struggle with various dysfunctions of body organs and systems and thus your health. It is not for nothing that scientists have proclaimed that “we are what we eat”. Indeed the first US Surgeon General’s report on Nutrition and Health (1988) stated: “For the two out of three adult Americans who do not smoke and do not drink excessively, one personal choice seems to influence long-term health prospects more than any other: what we eat”.

On the surface, it would appear that food is basically just that; food, the nicer it tastes the better and presumably the healthier. But science has shown that all foods are not the same regardless of taste. Sweet poisons abound just as much as delicious toxins; what is popularly referred to as ‘junk food’ does taste good.

To really understand the intricacies of what we eat, it is necessary to ‘digest’ food into its constituents so we can assess quantity and quality. Although food is essentially fuel for our bodies, we generally use food for more than just fuel; social eating is probably known in all cultures. The fuel part of food is determined by the energy content. Generally, this is measured in Calories (same as kilocalories). To get an idea of what the Calorie is, consider putting a container-full of one litre (1000cc) of water on a burner. To raise the temperature of the water by one degree Celsius requires one Calorie of energy.

Not every constituent of what we eat however yields energy on digestion - only carbohydrates (including fiber), fats, proteins, organic acids, polyols, and ethanol contain calories. Everything else in food, including water, vitamins, minerals, antioxidants, caffeine, spices and natural flavors is non-caloric. Non-caloric however does not mean non-nutritive, it just means the item does not yield energy on digestion.

The currency of food in terms of quantity is therefore the Calorie. This is where the difference comes – how much currency do the various foods yield in the nutritional bank of your body? If you take a gram of fat to the nutritional bank, the exchange rate is about 9 Calories. Carbohydrates yield 4 Calories per gram, proteins 4 Calories per gram and ethanol (alcohol) gives about 7 Calories per gram. Obviously, fat is the undisputed heavyweight currency champion and naturally, the body stores its excess energy in this form – it yields the most energy per gram when food is scarce and reserves must be called upon.

So how much food shall we eat? Simple answer – just what you need, provided supply is not a limiting factor. There were times when people ate as much as they could lay their hands on because there was no certainty as to when the next meal was coming. When you do not know when the next meal is coming, you essentially eat each meal as if it were your last. Sad to say, a large population of our world are forced to eat this way because of food scarcity. But granting you are blessed enough to escape this trap, how do we determine how much you need? Not so straightforward an answer this time; it depends. On what? Well, several factors, among them are your basal metabolic rate, activity level, your gender and your weight to mention a few. Am I going to go through a maze of such factors just to eat? Frankly, scientists have a peculiar way of complicating the simple things of life. One man’s solution was simply this: ‘Eat whatever you desire, drink anything that tastes good, and be merry all the days of your life’; and he was also quick to add ‘But remember the judgment.’ Now that got me, because it hit home that whatever food choice one makes, a day of judgment ultimately arrives, often so remote from the time the choices were made that all association is lost on the chooser. Scientists tried to simplify all the maze of factors into one statement “Recommended daily energy intake values for young adults are: 2500 Calories/day for men and 2000 Calories/day for women.” However, if you have a small build, you probably require less; if your daily job requires heavy physical input, you probably require more. The reason we need to take Calories seriously is that ultimately, your Calorie balance determines your body weight (and everything else linked to that). Not only that, research also indicates that restricting your caloric intake (scientists refer to this as Caloric Restriction) actually prolongs your life!