In my last post, I underwent a scientific ramble upon the subject of fat, going into a little of the basic chemistry and biology of the whole business. However, what I did not touch so much on is the giant elephant in the room that surrounds all talk of fat in our modern world, and looks poised to become one of the defining issues of the twenty-first century- that of obesity and overweightness.
I am not, however, about to analyse obesity as a whole in this post, but instead intend to consider why attempting to counteract this, and the slimming industry in general, have become such major bones of contention for so many people. There’s no denying that the slimming industry is worth a veritable fortune- one analyst I saw on TV the other day estimated that a simple cure-all for the world’s obesity problem could be worth up to four trillion dollars, particularly given the boom in public obesity in countries like Brazil and China. However, this doesn’t mean that slimming is popular or that everyone goes in for it- if slimming down weren’t such a problem for so many people, there wouldn’t be an obesity problem worth speaking of, and it’s an open secret that around 99.9% people attempting a new diet fail to keep any weight off in the long term.
To begin, let us consult the very basics. For practical purposes in terms of losing weight, fat is basically energy stored by your body in physical form; the formation of the triglyceride molecules that make up fat requires energy, ‘using up’ any excess energy your body may have, and breaking them apart (the leftover ‘bits’ of the broken-down triglyceride molecules are effectively waste products that are transported to the kidneys via the bloodstream, and are later eliminated from the body in urine) releases this stored energy for your body to use, in order to keep your various bodily functions going and allowing you to move around and do things. Thus, any difference between the amount of energy your body consumes (in food, mainly; a ‘calorie’ is nothing more than an old unit of energy, just like the ‘joule’ unit used in modern science) and uses is offset by your fat reserves- if you put in more than you get out, your fat stores increases, and vice-versa. Thus, the only real challenge facing a slimmer wanting to shed their excess fat is to expend more energy than they consume (leaving to one side for this post various claims that certain foods make you fatter than equivalents of a similar calorific value). Just so we’re all clear on this.
The first concern to raise its ugly head when considering this problem is the simple question of ‘how much energy do we actually expend per day?’. Many people will look to the little table of government-issued Guideline Daily Amounts of various nutrients that you find on the side of most food packaging, but it must be remembered that these are only ‘Guidelines’ after all and a more personal evaluation may be of use. The amount of energy your body uses per day is known as your Metabolic Rate, and a good starting point for an aspiring slimmer would be to calculate your Resting Metabolic Rate (RMR). One’s RMR is a measure of how much energy a person of your gender, age, height and weight would normally (some people may have unusually fast or slow metabolisms, but these people are rare and ‘I have a slow metabolism’ is more often an exuse than reality) expend per day were they utterly at rest; not moving, not doing anything, this is the minimum amount of energy your body needs in order to function. RMR calculators such as this one are freely available online, and that one also features a separate calculator (under ‘Calorie Calculator) that allows you to (very roughly) estimate your total calorie consumption per day. The final number you get out of this latter process is a very useful guideline to the aspiring slimmer.
However, simply aiming to eat less than that number is no guarantee of long-term weight loss. For one thing, many people give up on diets because they can see no immediate results, but this is because ‘burning’ fat is an inherently slow progress. Depending on your source, fat stores between 7500 and 9000 calories per kilogram, meaning that if you are on a diet in which you eat 500 calories less than you expend (and I’m being generous here; a 500 calorie shortfall will leave you feeling very hungry), you can only expect to lose a kilogram of fat every 2-3 weeks. Even this may be masked if our hypothetical slimmer decides to exercise a bit more too; regular exercise will cause a person to put on muscle (which weighs more than fat) and thus make the loss of weight seem less impressive- but we’ll come onto exercise in a minute.
The other major issue facing those who try to lose weight by dieting is the fact that diets are really, really unpleasant. For one thing, the constant calorie-counting provides unwanted mental strain for many (hence the popularity of points-based diets and similar that do the calculations for you), and this mental fatigue can serve to only exacerbate the gnawing hunger in our empty bellies at the end of a day when we’ve eaten enough calories but not enough to satisfy our stomach. Not only do dieters frequently feel hungry, they also have to deal with a bland diet of lettuce and cottage cheese- and however much we can pretend that we find these delicate things delicious, they don’t quite compare to the stomach-filling satisfaction of a thick, fatty, meaty burger.
The problem is that our hunger is not dictated by how many calories we have consumed, but by how physically full our stomach is, and whilst there are a few tricks that can be used to try and counteract this (a personal favourite is to down a pint of water when feeling peckish, just to give my stomach a large physical amount of stuff to process) none of them really compare to everyone’s dream of being able to eat as much as they like and still not get thin. So, if attempting to limit our intake of energy alone isn’t enough (although diet is most certainly a vital part of keeping our weight down), our only remaining option is to increase the amount of energy we expend, and that means exercise.
The benefits of exercise in relation to weight loss are generally poorly understood by most people; whilst the very act of getting our bodies moving does expend energy, as the little calorie meter on an exercise regime may show, the actual amount of excess energy expended by this process is usually very little; a half-hour run may only expend a cupcake’s worth of energy. No, the real benefits to exercise concern the metabolism; exercise and leading a generally active lifestyle causes your overall metabolic rate to rise, which is why relatively short but regular bouts of exercise (which constantly ‘top up’ one’s metabolic rate) are generally more productive than a four hour long weekend blowout that only boosts the metabolic rate for a small portion of one’s week. This is why the oft-quoted adage instructing people to do 10,000 steps per day has hung around for so long; I honestly believe that were everyone to follow this advice, there would not be a serious obesity problem. Not only that, but as mentioned before exercise, particularly intense exercise such as sprinting or weight training, will build muscle- muscle whose cells will need to be constantly provided with energy in order to stay alive, thus increasing one’s metabolic rate in the long- as well as short-term.
One final pitfall to be noted with attempting to lose weight in this fashion involves attempting to keep it off. It must be borne in mind that people of a lower weight have a lower RMR and thus need less energy, meaning that if a successful dieter reverts to their pre-diet practices they will be eating too much and will just balloon back to the weight they were. Thus, when one makes a commitment to exercise or better eating it has got to be a genuine change in lifestyle (something very few people are willing to commit to) in order to work for the long-term.
That’s one of two reasons why an unpleasant diet of celery sticks probably isn’t a great weight loss solution; the other reason concerns the other benefit of exercise. Someone who regularly exercises isn’t just likely to be slimmer than a similar person who doesn’t, but to be healthier as well- their heart will be healthier, their muscles more able to perform practical real-world tasks, and their body is generally less likely to suffer from the ravages of time and disease. A lot of the stated health problems that come from being overweight or obese are merely symptomatic of people who eat bad food and don’t exercise sufficiently, rather than being directly caused by being overweight. That’s why very few people worry after the cardiovascular health of Jonny Wilkinson, World Cup-winning rugby star and shining light of Toulon RC: a man whose BMI classes him as morbidly obese.