Obesity is one of the top three social burdens generated by human beings and costs the world as much as the number one - war, armed violence and terrorism - and number two, smoking. Yet existing evidence indicates that no single intervention is likely to have a significant overall impact in reducing it.

That's just one of many depressing conclusions of the recently produced McKinsey Global Institute report. The report recommended widespread intervention including restructuring urban and education environments to facilitate physical activities but had to admit that no one really knew what they were doing.

In the wider world of physical activity and fitness and I wonder how many would be as honest and admit we don't really know what we're doing either? Education and personal responsibility are critical elements of any programme aiming to reduce obesity and increase fitness levels but both are a lot more difficult and require greater will power than giving into the trend to over-eat and over-drink. It would be easier if people just ate less and exercised more but the temptation provided by sugar, fat and salt laden products, oh, and lets add alcohol too, which gives a short term high compared to the aches and pains from exercising. Exercise sadly offers many empty promises to the masses while only a few get the endomorph.

Food industry experts constantly disagree on the science of eating and fitness industry experts find little common ground on weight loss for mere mortals, let alone achievements for the body obsessive. As Duncan Green mentioned in a recent article the slimming industry has cheap scales and an industry four times the size. The fitness industry have strength and resistance training, cardio workouts, limit testing classes, high, and, or, low intensity classes, dual habits, indoor and outdoor military style bootcamps, not to mention the flexibility, dynamic, static, and anaerobic workouts, to name but a few. Everyone has a pet theory, a snippet of knowledge and an article from a celebrity or DVD or blog on what works best. Albert Einstein said 'whatever we're looking at we don't understand it' and as the debate rages amongst the experts and new 'solutions' appear each month you realise Albert was right.

Even the government produce five fact sheets on physical activity guidelines and fact sheet 4, for Adults 19-64 years, suggests we should be 'active' daily and over a week should add up to at least 150 minutes of 'moderate intensity.' Harvard Medical School publish calories burned in 30 minutes for people of three different weight ranges with over 100 activities listed by categories including 'gym activities', 'sports', 'outdoor', 'home', 'daily life' and 'occupational'. So if you're running a 6 minute mile and you weigh 185 pounds in 30 minutes you burn 733 calories, compared to sitting at your computer only burns 61. Giving guidance for a whole nation can only be general at best in the hope that self interest and education may kick in but short term history tells us that the number three social burden generated by humans will be with us for some time as no one understands it.

David Minton, Director The Leisure Database Company, www.leisuredb.com