Is losing weight simply a case of eating less?

Why is it that some of us can eat what we like and not seem to put on any weight, while others watch what they eat, count calories and are endlessly struggling to lose weight?

Why are some of us hugely obese and others very thin? Is it simply a case of food or are there other explanations? Obviously food plays a large part in our shapes and sizes. If I spent all day eating fast foods, drinking fizzy sugary drinks and snacking on cakes and chocolates in between meals, I would probably be a lot larger than I am now.

I'm not a dieter or calorie counter and my weight has been around 9 stone for as long as I can remember in my adult life. I eat what I want and snack from time to time, I drink alcohol in moderation, but now that I think about it, I hardly consume any calories with my soft drinks. So what if I started eating as mentioned above? How big would I actually get?

A few years ago, Horizon broadcast a documentary on why thin people don't seem to put on weight easily. They took 10 thin volunteers, who found it difficult to put on weight, and carried out an experiment to see if after consuming double their recommended daily calories and limiting their daily activity to just 500 steps, how much weight they would gain.

The women had to consume 7,000 calories a day, (the average woman needs about 2000 calories a day) while the men had to consume 10,000! (the average man need about 2500 calories a day). They had to eat as many burgers, chips, cakes, ice-cream and pizza as they could possibly keep down, to get up to the calorie intake requirement. And they could only walk a short distance each day. The experiment lasted 4 weeks and the results were quite shocking in some cases.

Two members were unable to consume the designated amount of calories each day failing to complete the experiment. One member was a sportsman who found it too difficult to stick to the 500 steps a day. Five of the other members, although reaching their daily calorie targets, were unable to keep the food down and vomited at least once a week. One of these was recorded to have gained 3.5kg in weight (almost 7% gain) and another 5.5kg (9% gain). It was later reported that all the weight gained by these volunteers was easily shed without any need to diet or count calories.

Only two members of the experiment reached their target. One gained 0.5kg (1% gain in body weight) while the other put on 5.7kg of muscle! Yes muscle! His body fat percentage actually went down slightly!

Dr Rudy Leibel of Columbia University, New York believes "we all have a biologically determined natural weight which our bodies make an effort to stick to, whether it is fat or thin ... The body will constantly tend to try to bring you back to whatever your normal body weight is". Dr Leibel found that for some people, such as those who couldn't reach their calorie targets, the appetite hardly fluctuated regardless of how much they wanted, or were told, to eat.

In this Horizon documentary, there was a brief mention of an experiment which had taken place in a prison in America back in the 60's. I can't find anything about it now so I'm going completely from memory here. An obese inmate volunteered to take part in an experiment to reduce his weigh in exchange for early release from prison. (A Clockwork Orange springs to mind). He was kept on a strict diet for a year until he reached a normal, healthy weight and was then given enough food each day to sustain this weight permanently.

Although the amount of food he was consuming at this stage was perfectly acceptable for his size, the inmate was constantly complaining that he was still hungry. He was attached to a monitor and his brain was registering a person in a state of starvation. How could this be?

This proved that the only way this man could remain a healthy weight, would be to live his life in a constant state of starvation. (Now I don't know about you, but I think I'd rather eat and be fat, than live my life literally starving. Gina Kolata writes an interesting paper where she mentions "semi-starvation neurosis". Have a read if you like what I've written so far).

Professor Jane Wardle, believes that there is a gene known as the FTO gene which could have an affect on our weight. She believes the gene can influence appetite, leading some people to not know when they are full. Those without the gene, she thinks, find it easier to say 'no' to food. "It's kind of effortless because they don't even want to eat. They're not having to exert willpower and self-control whereas for other people, their brain responses to foods that they're exposed to, aren't being switched off effectively as a consequence of them already having had enough."

I now beleive that our weight is genetic and it is possible for two people to eat exactly the same amount of food and put on very different amounts of weight. Perhaps a great explanation is evolution. This is what I think. If you evolved from a tribe of hunters, you'll probably be in the overweight category. In the days where man had to hunt for his food he would gorge himself with whatever was available to eat when food was plentiful, piling on the fat which would sustain him for the months ahead when food was less easy to come by. Those who could not keep the weight on would simply starve to death. Leaving a large group of potentially obese people.

If you evolved from a tribe where food was never a problem and was plentiful all year round, you would probably fall into the thin category. Why would you need to develop the ability to store fat if you didn't have to? You would simply eat what you needed until the next meal.

I like Dr Leibel's theory about our bodies always trying to bring us back to whatever our natural weight is. So if you're constantly fighting a battle of weight loss, perhaps this post will give you a possible explanation as to why.
However; whatever way you look at it, you can't change the laws of physics. The more calories you consume, the more weight you'll gain and the more you work off, the more weight you'll lose.