The human body is a pretty complex machine but it has simple fuel needs: Enough calories to replace those we burn, enough water to replenish what we expel (principally through sweat and urine) and some basic micronutrients that we will invariably consume if we eat a variety of foods.
So, for time immemorial, we have harvested fruits, vegetables and grains and hunted or raised livestock for meat. For drink there was water, precious water, and, in some parts of the world, milk.
But, damn, we like to complicate things.
Consider what we drink. Instead of water, pure and simple, we have an endless variety of drink, many bolstered with more sweeteners, natural or artificial, and often highly caloric.
What we raise in our cup is symbolic of how we have become far removed from our food sources. Food no longer comes directly from a family farm, it comes from a supermarket (or, increasingly, a restaurant) via an agro-industrial operation. Even water doesn't come from a well or the tap; it comes in a truck to the supermarket.
The yields from modern fields (or greenhouses) are amazing thanks to efficiencies of scale, fertilizer and antibiotics. But the end product – what we used to call "food" – often leaves a lot to be desired.
Food is rarely fresh any more: It's frozen, freeze-dried, canned, processed and packaged. It's larded up with salt, sugar, preservatives and additives, then wrapped in plastic, bagged and boxed. All this to make it more attractive and, presumably, more palatable.
Even the "fresh" foods, mass-harvested and shipped around the world, tend to be devoid of taste, and often nutrients as well.
The result of these "improvements" is that we now have more malnourished people on Earth than ever in history, in absolute and relative terms.
Malnourished used to mean those who were starving, usually as the result of drought or war-related famine. Today, there are more people on the planet who are overfed than underfed. In much of the world, Coke is easier to find that fresh water.
In Canada, according to a 2010 Statistics Canada report, approximately 61 per cent of men and 44 per cent of women are overweight, a figure that includes roughly 20 per cent of men and 17 per cent of women who are classified as obese.
People get fat because they consistently consume more calories than they burn – it's a fairly simple mathematical equation.
There are those who challenge this bare-bones science, arguing that the type of foods we eat – principally carbohydrates versus proteins – matter a whole heck of a lot too. The how-many-angels-can-dance-on-a-pinhead arguments are endless.
Suffice to say that how and why we consume the calories we do in the quantities we do is as complex as it is puzzling. Just saying "no" doesn't cut it.
What we do know is that, genetically, homo sapiens are built for a world of famine and feast – meaning our bodies store fat easily.
But these days it's all feast, at least in wealthy countries like Canada.
Food is plentiful and easily accessible and bad food is more plentiful and more easily accessible.
Of course, there are countless diet books – ranging from sensible advice to outright quackery – and all manner of commercial weight-loss programs to help individuals fight the battle of the bulge.
There are also trends that come and go. For a long time, we fought a war on fat, failing to distinguish between good and bad fats. The result was a wave of low-fat foods, where fat was replaced with salt and sugar. Then there was the carbs-are-the-enemy era, when protein was king.
These days, the villain of choice appears to be beverages.
While it will no doubt prove to not be a panacea, focusing a spotlight on what we drink is certainly a worthwhile endeavour, both individually and collectively.
After all, it is estimated that 20 to 40 per cent of all the calories we consume are liquid calories.
That is an enormous change from a generation ago; our drink consumption patterns have changed much more dramatically than our food consumption ones.
Last year, Statistics Canada reported that Canadians consume, on average, 26 teaspoons of sugar daily. What was not highlighted nearly enough was that the principal sources of that sugar were milk, pop and fruit juice.
Two of those three beverages are generally considered to be healthy, natural foods. But natural is not necessarily a synonym for healthy.
Chocolate milk has, ounce per ounce, almost twice as many calories as Coke. And a cup of juice contains as much as 10 teaspoons of sugar – the equivalent of drinking a 1/4 cup of pure maple syrup.
For example, Dr. Yoni Freedhoff, a bariatric surgeon who writes the popular food blog Weighty Matters, calls grape juice the "world's least healthy beverage."
This does not mean these beverages should not be consumed, but moderation is the key. The Canadian Paediatric Society, for example, says young children should not drink more than 1/2 cup of juice daily, and big kids no more than one cup.
Limiting sugary soft drinks (which contain fructose corn syrup, not even real sugar), or avoiding them altogether, is a no-brainer. Diet soft drinks are not nearly as bad because they are calorie-free, but there is growing evidence that artificial sweeteners pique interest for other sweets, which defeats the purpose.
All that to say, that the best beverage to have as the basis for a healthy diet is water – not vitamin water, not expensive sparkling water shipped from France, not bottled water, though a pretty good case can be made for some of its variants, like tea and coffee (as long as they are not loaded up with sugar and cream).
But, in our quest to find solutions to the bedevilling obesity epidemic, one of the most elemental building blocks for a healthier life is at our fingertips – and it comes out of the tap for free.