The concept that obesity is a risk to health was clearly identified in the works of Hippocrates and frequently over the ensuing centuries. Obesity was originally discussed as part of more general texts. Scholarly theses on this subject began to appear in the late 16th century with the first monographs published in the 18th century. The value of dietary restriction, increasing exercise and reducing the amount of sleep were identified early in medical history dating at least from the time of Hippocrates. These concepts were often framed in a manner which implied a 'moral' weakness on the part of the overweight individual. The most spectacular dietary success was published by a layman in 1863 and was the forerunner to many subsequent diet books. Cases of massive obesity were identified in stone age carvings and have been described frequently since the time of Galen and the Roman Empire. More specific types of obesity began to be identified in the 19th century. Following the identification of the cell as the basic building block of animals and plants, fat cells were described and the possibility that obesity was due to too many fat cells was suggested. After the introduction of the calorimeter by Lavoisier, the suggestion that obesity might represent a metabolic derangement has been suggested and tested. Standards for measuring body weight appeared in the 19th century. The possibility that familial factors might also be involved was clearly identified in the 18th and 19th century. In conclusion, most of the concepts which are currently the basis for research in the field of obesity had their origin in the 19th century and often earlier.