The driving force is the the planet's intense internal heat. Now, new experiments show that small and formerly overlooked variations in chemical composition determine the type of convection. More than two centuries of draft age Frenchmen have passed military medical examinations. Doctors recorded their weight and height. The advent of computers now enables scientists to use this data to study a new and emerging feature, obesity in young adults.
Different patterns show up across the country.
In the mid-nineteenth century, a Belgian statistician observed that the ratio of weight over height squared of normally constituted individuals produces a constant. This simple body weight index has become a widely used tool in the doctor's office and in public health. Disorganization of eating habits in the Western world could aggravate the effects. If the consequences of simply being overweight are still subject to discussion, there is no longer any question that obesity is associated with physiological complications and higher mortality. In animals, mutations of certain genes can lead to animal obesity.