After the London meeting, obesity conferences evolved from local to international affairs. The first was in Paris in 1971, hosted by European nutrition and dietetics associations. Here the sole presentation on the dietary treatment of obesity was by a collaboration from the French National Institute on Health and Medical Research (INSERM), which is the local counterpart of the NIH in the United States and the Medical Research Council in the United Kingdom. These INSERM investigators had prescribed diets of twelve to eighteen hundred calories to over a hundred obese patients, in either three or seven meals a day, and with varying amounts of carbohydrates. Weight loss increased, they reported, when the subjects divided their calories among seven meals, which served to moderate the insulin response. Moreover, “lowering the carbohydrate content of the diet increased the weight loss at both meal frequencies.”

The next conference was hosted by the NIH in Bethesda, Maryland, in October 1973. Six of the presentations at this meeting discussed the treatment of obesity by methods other than drugs or surgery. Two were on physical activity, and neither reported any significant effect of exercise on body weight. Two addressed the benefits of behavioral modification on weight loss, and neither reported any significant benefit. Of the two remaining presentations, one was by Ernst Drenick of UCLA on prolonged fasting to treat obesity—“our experiences are disappointing,” said Drenick—and the other was by Charlotte Young of Cornell on dietary treatments.

As Howard had in London, Young reviewed the hundred-year history of carbohydrate-restricted diets, including the research of Pennington and that of Margaret Ohlson and her own trials in the 1950s. Young then discussed her recent studies, in which she had put obese young men on eighteen-hundred-calorie diets with the protein content fixed at 460 calories (26 percent), but with varying proportions of fat and carbohydrates. Over the course of nine weeks, she reported, “weight loss, fat loss, and percent weight loss as fat appeared to be inversely related to the level of carbohydrate in the diets”—in other words, the fewer carbohydrates and the more fat in the diet, the greater the weight loss and the greater the fat loss. “No adequate explanation could be given for the differences in weight losses,” she said. All of the carbohydrate-restricted diets, she said, “gave excellent clinical results as measured by freedom from hunger, allaying of excessive fatigue, satisfactory weight loss, suitability for long term weight reduction and subsequent weight control.”