It’s that time of year, when all we see or hear on the tabloid pages and internet news sites is diet diet diet. A healthy diet is not one you’ll lose weight on, and being slightly overweight is healthier than you think. But for those who wish to purge the holiday poundage, kill the Christmas kilos, and shift that stubborn few stone, a short-term fad diet is the route you’ll probably take.
Weight loss dieting is much easier than it's made it out to be. It’s simple mathematics. Burn more energy than you consume in food. Translation: work-out more and put down the pastries. The numbers on your internal energy balance sheet always have to add up. Your cells need energy to function and they’ll get it by scavenging from your own body if you starve them a little.
[caption id="attachment_91" align="alignleft" width="300"] Food! Image courtesy of epsos.de, available under Creative Commons licence 2.0[/caption]
The other side of this coin is that if you don’t eat enough essential nutrients, like amino acids and vitamins, your body and health will suffer. Amino acids, the building blocks of protein, will be scavenged from your muscles. Some vitamins, minerals, amino acids, oils, and fatty acids are essential for us to function properly. That can’t be stressed enough. If you’re planning to lose weight by eating less, ensure that you don’t cut these essential elements out. Balance is ultimately the key to healthy eating and weight loss.
The currency of energy
We’ve mentioned energy. Energy in food is more familiar to us as nutritional calories (or kilocalories). A kilocalorie is defined as a unit of heat energy. If you pour out one kilogram of water into a bucket, stick your arm and a thermometer in there, and see the temperature rise by one degree Celsius, then you've just burnt a kilocalorie! So the energy contained in a 200 kilocalorie bar of chocolate (like those found beside the checkout at the shop) could boil two kg of water if that energy was converted directly into heat. Think about it, humans are mostly water, weigh roughly 60-80 kg and maintain a steady 37 C body temperature; it’s easy to see how your body does this. Energy from food and stored energy is released in a controlled process and translated into the heat that keeps us alive.
Energy is released from sugars, fats, and proteins obtained from food. Their breakdown gives off heat in what’s called an exothermic reaction. Simple sugars are converted to glycogen and stored in muscles for easy burning when we’re not eating. When the glycogen stores fill up, the sugars are converted to fats called triglycerides for later burning when our glycogen runs out and we still haven’t eaten. This is particularly useful when we get ill and can’t eat. Your body can run off the energy stored in our fat without compromising our other tissues to great extents during illness.
Ultimately, the healthiest diet to be on is a balanced one (duh) with plenty of fresh vegetables, fruit, lean meat, fish and some carbs. Indulgence in the sugary/fatty junk-food treats should be done sparingly. Exercise often and drink lots of water. Want to lose weight? Simply adjust the balance: eat a little less of everything and exercise a little more. It’s slow, but healthy, and remember fat has its uses – it might just save your life – so don’t lose it all.
Here are some weird weight-loss diets – they all work to some extent because they restrict your food intake (even if some promise you replacements, energetically the balance is usually a net loss for your body so you end up burning fat). Take them with a pinch of salt, however – they aren’t all that good for you.
Fats are good. Proteins are good. Most veggies are good. But don’t even think about going near that potato. Don’t even look at it! Carbs are evil on Atkins. The diet "phases out" carbs over time, and has been praised for raising HDL (good) cholesterol levels. This diet was criticised for having potentially dangerous levels of saturated animal fats. Atkins himself died of a heart attack having lived on this diet, though the diet was unrelated. (Doctors noted his arteries were "very clean"). Those on the Atkins diet have complained that after 12 months, the weight loss peters out and that weight is regained quickly once carbs are reintroduced.
“Doctor” Dukan’s diet is very much like the Atkins diet – limiting carbs to near-zero but promoting low-fat, low-sugar, lean meat and limited vegetable consumption. Weight loss inevitably occurs, since you end up eating a slice of turkey breast and a leaf of lettuce every day. This works up to a point for weight loss, but is not a nutritious or balanced diet for long-term use.
I’ve often wondered what Richard Dawkins would say about this diet, which is based on what we would have eaten as “cavemen”. This diet recommends lots of unprocessed meat and fish, and frowns upon carbs, grains (gluten), dairy, refined sugar and anything else our ancestors didn’t have in the Stone Age. The logic behind this diet is partially flawed, however. Our digestive systems have changed to accommodate different foods over the last 10,000 years, in part thanks to the bacteria that inhabit our gut and genetic adaptations that allow us to process lactose, the sugar in milk, as adults. To assume grains and milk are “unhealthy” on these grounds is absolutely ludicrous.
5:2 or alternative fasting diet
This one, promoted by BBC’s Dr Michael Mosley, hardly needs explaining. Balanced diet five days a week, fast for two days a week. The idea is that you won’t eat so much on the non-fasting days that it would undo your days of fasting. Fasting also has benefits regarding insulin production, lowering blood pressure, reducing diabetes risk, and living longer. (Although this latter claim is disputed since the process of “caloric restriction” – eating substantially less than your recommended daily requirement of calories – may also lead to increased contraction of/death from illnesses). The 5:2 diet, properly administered and tapered down to a 6:1 once the goal weight is reached, is nutritionally the best of a bad bunch. However, the sheer strength of will to fast is not for everyone.
The right weigh to go
Balanced diets are recommended by the World Health Organisation as the way to go for day-to-day healthy eating, and increased exercise is generally considered the best way to lose weight. Fats aren’t necessarily bad and sugars in high amounts are not good. Low-fat foods tend to contain high amounts of sugar which, as we now know, is stored as fat in our bodies. Are artificially low-fat foods really that helpful to us?
Find out in Part 2: The good, the bad, and the sugary.