The Science of Weight LossLast Updated: June 21, 2021
There is way too much information on the loose about how to lose weight. Way too much to easily spot good advice, which is like trying to find two halves of a needle in five different haystacks: and someone's painted them yellow!
It's easy to forget among all the competing (and downright conflicting) advice that weight loss IS a science. We do actually understand the biological mechanisms that result in gaining weight, and losing it. It's actually quite straightforward. The real problem is one of self control.
But first, the basics!
The Biology of Weight Loss
Body fat, also known as adipose tissue, is the body's main way of storing energy, as well as cushioning and insulating the body. That's right, fat isn't there just to punish you for eating! When your body ingests more energy than it needs to function, it saves that energy as fat for future use. Having some body fat is perfectly healthy.
The problem is, most of us today don't need to worry about surviving through long winter months with minimal food. So all that extra energy our bodies hold onto as fat just keeps building up, and building up, and building up: until we go way past the healthy ranges. On top of that, most of us work sedentary jobs and travel by car or metro, meaning we get little to no exercise to burn the calories we consume every day.
But that's all there is to it: eating less or moving more. Study after study has confirmed that all weight loss comes down to calories in versus calories out. The exact speed varies from person to person, but the math doesn't lie: a calorie is a calorie is a calorie, whether it comes in the hundreds per bite of chocolate cheese cake, or per entire meal of fruits and veggies. Every pound you've ever gained is the result of eating more calories than you burned, and every pound you've ever lost is from eating less than you burned.
It really is that simple. So, in theory, weight loss is a cinch, right? Just eat less calorie-rich food and be more active to burn what you eat. Easy peasy.
Ha! Yeah right. We all know it's not nearly that simple. And the reason why brings us to:
The Psychology of Weight Loss
A calorie is a calorie, as we covered earlier. Putting aside questions of nutrition and vitamins, as far as body fat generation is concerned, two thousand calories of nothing but ice cream with chocolate fudge and marshmallows is equivalent to two thousand calories of vegetables and grilled chicken.
But the obvious difference is that you will reach the two thousand mark much faster with ice cream than you will with the chicken salad: and you'll be less full as a result.
And what happens when you feel less full? You eat more!
Which is why even if a calorie is a calorie, there absolutely are some foods better for dieting than others. Namely, food that's low on calories, but tasty and filling. Otherwise, your body feels like you're starving it (which you are!), especially since it's getting less calories than it's used to as well. That's why so many diets fail: trying to lose weight by eating nothing but celery sticks can be torturous, and the psychological pressure to break the diet becomes overwhelming.
But wait, it's even worse than that. While exercising is one of the healthiest and most beneficial things you can do for yourself, one of the most common mistakes among people trying to lose weight is trying to exercise without putting strong limits on their calorie intake. So they go for a jog, thinking they're burning off the calories of the burger they had at lunch (unlikely, unless it was a tiny burger), and when they get home, they're exhausted, and their body perceives a calorie deficiency of what it's used to, signaling hunger and a desire to restock and "reward" yourself. A couple chocolate chip cookies might satisfy the craving: but now you've just eaten back all the calories you lost from the jog!
This vicious cycle is at the core of what makes losing weight so hard: exercise is healthier for you than just cutting calories, but cutting calories is easier than exercising for losing weight. Maintenance of a healthy weight requires exercise, but for losing weight, cutting calories is much easier. A medium fries from McDonalds is 380 calories. It takes almost two hours of walking to burn that! And of course afterwards you'll be exhausted and hungry again soon.
So if you have to choose between cutting calories and exercising to lose weight, the best thing you can do first is try to manage your appetite and build up your willpower. Despite popular wisdom, the amount of effort both take are not equivalent to their results.