The latest issue of the Journal of the American Medical Association holds two studies about obesity trends in the U.S. Their basic finding: the rates are slowing down a bit, bit they still ain’t good. Two-thirds of adults, and one-third of children, are overweight or obese.

Obesity, writes J. Michael Gaziano in a related commentary, constitutes the fifth phase of the epidemiologic transition. That’s a mouthful, I know, but he writes a really fascinating (and brief) history of human disease. Here’s a snippet:

The first stage, which dominated most of human history, was characterized by pestilence and famine, when infectious disease and malnutrition kept average life expectancy at about 30 years. In the second stage, occurring in the late 19th and early 20th centuries in the United States and Europe, industrialization and urbanization led to increasing wealth and a corresponding increase in the availability of food, an era termed receding pandemics. As the century continued, public health systems and cleaner water supplies and sewage systems combined with better nutrition drove down deaths from infectious disease and malnutrition, leading to declining infant and child mortality and an increased life expectancy. The third stage, degenerative and human-made diseases, characterized by increasing mortality from cardiovascular disease and cancer, emerged in the mid 20th century. Smoking, decreased activity levels in the workplace and at home, and increased intake of animal products and fats resulted in increasing prevalence of elevated blood pressure and cholesterol levels. Age-adjusted cardiovascular disease and cancer rates were at their peak.

By the mid 1960s, the United States had entered the fourth stage of delayed degenerative diseases. Cardiovascular disease mortality declined, related to preventive strategies such as smoking cessation programs and effective blood pressure control, acute coronary care units, and technological advances that included coronary artery bypass surgery.5

Despite the many advances in preventive medicine and treatment that reduced cardiovascular disease, the new stage of the epidemiologic transition, the age of obesity and inactivity, emerged to threaten the progress made in postponing illness and death to later in adult life spans. The steady gains made in both quality of life and longevity by addressing risk factors such as smoking, hypertension, and dyslipidemia are threatened by the obesity epidemic.