Exercise for weight loss - does it really work?

Scotland has a growing obesity epidemic, which stood at about 27% in 2013, with 60% of our population overweight. This is estimated to cost the nation  between £600 million (NHS costs) and £4 billion (loss of productivity, early deaths etc). Either way, it is a lot of money!

At any gym in January, you’ll see the same scene every year; the room is crammed with overweight people trying to lose weight in preparation for spring weddings and holidays or for wake-up calls to health.

It occurred to the cynical side of me that their effort may be futile. Exercise is less effective for fat loss than we think. You don't believe me? Well, most people trying to lose weight are very conscious of calorie expenditure, but I have some bad news for you all.........

Let's suppose you jog for 30 minutes, at 10 kph (~6 mph), assuming that an overweight, unconditioned person can do that. The calorie charts and the treadmill will tell you that you have burned about 400 kcals, depending on your size (big people burn more energy than small). Now, if you stop jogging and sit down, you will burn ~150 kcals in 30 minutes, just sitting there. Why? Because your metabolism - all the necessary things to maintain life, such as breathing, blinking, digestion, heart-beat, thinking etc - requires energy. In other words, the 400 kcals burned is actually a net deficit of only ~250 kcals after 30 minutes of hard effort. Sorry!

There is more bad news; exercise may make us gain weight because it makes us hungry. Some may object - doesn't exercise suppress appetite? Well yes, while you are exercising, but when we stop, the body's first priority is to re-establish the status quo. This is a biological necessity for survival. The organism's first priority is restoration and repair. If, like me, you keep a food diary (www.myfitnesspal.com), you may notice that your calorie intake and appetite increases after exercise, either later that day or the next.

I was talking to a client the other day. about his running across the Pentland Hills, which lie to the south of Edinburgh. That morning, he had run for over 2 hours over rough ground in a stiff, cold wind. I asked him how he felt and how hungry he was. He wasn’t hungry because he'd had a huge post-running meal a couple of hours before coming to the gym for strength training. He agreed that his appetite was increased by running, but he said also, he had lost weight running in the past and his female colleagues were glad to either maintain their weight and eat well, or lose weight, by hill running.

So, that contradicts me, right? Well, in the man's case, he admitted that his previous weight loss had only been achievable through this repeated intense effort with hunger. He had continually and strictly under-eaten, below his appetite, in the past, after running, to achieve a particular weight goal. He was constantly hungry during that period because he was on a low-calorie die, relative to his needs. This is the experience of most people who try to lose weight by exercise and/or by low-calorie diets. Eventually, the body wins the fight and the weight is regained to safeguard its equilibrium.

Does this mean that exercise is a waste of time in weight loss programs? Not at all. Long-distance cyclists and runners are examples of leanness through exercise, but their training requires hours of steady state activity every day, combined with shorter periods of intense effort. This is something which requires dedication and motivation beyond the reach of most overweight people.

It is clear that we are designed for movement - we have muscles and a cardiovascular system to support them. The gym industry is growing because it replaces the activity that is lost in our lives by sedentary "work", sitting all day, moving a computer mouse or holding a pen or telephone. People who do real work, in the physics sense, don't need gym memberships because they are walking, climbing, lifting, carrying, moving, all day long, using their muscles, burning energy and depleting their muscle glycogen levels, unlike their sedentary counterparts.

If moderate exercise three times per week (the usual formula) has little effect on weight loss, then how can we lose excess fat? In future posts, I shall address this problem and explain why counting calories doesn't work , then I'll tell you about a weight loss diet that actually works - even without exercise.


Please go to my Update on 13 June.