"As I get older I sometimes feel as though I’m watching an airport luggage carousel, seeing the same old suitcases trundling around, except that in my case I’m looking at scientific research. In fact I wonder if today’s scientists ever read the published literature, because over and over again I see “original” studies which simply repeat work which was done perfectly well 10 or even 20 years earlier.
"The latest example is from Professor John Speakman of the University of Aberdeen who has come up with the illuminating insight that increasing physical activity alone will not reverse the obesity epidemic and that we will also have to reduce the nation’s food intake. This observation must be blindingly obvious to anyone with even the most modest mathematical skills. If you want to lose 1lb of weight per week, you will need to reduce your daily intake by around 500 calories. You could do this fairly painlessly by reducing your food/alcohol intake, but if you want to do this through physical activity alone you will need a brisk walk of 1½ - 2hours each day (depending on your body weight).
"But what Professor Speakman misses, is that regular physical activity helps to preserve and increase lean (muscle) mass, which has a direct impact on metabolic rate and which has other important health benefits. This means that although physical activity may not in itself be hugely effective in promoting weight loss, it is extremely effective in helping people to maintain their new weight once they have achieved it. This has been shown in numerous studies over the last several decades.
"So, the simple truth is that the best way to achieve and maintain a healthier weight is through a combination of diet and physical activity. Oddly enough, I think most of the 25 million people currently trying to lose weight already knew that!"