The Food and Drug Administration will consider this week whether to lower the minimum weight allowed for people to be eligible for weight-loss surgery—which would make the option available to millions more people. The pharmaceutical company Allergan, known mainly as the makers of Botox, has petitioned the FDA to make the Lap-Band operation available to those with a body mass index of a mere 35, greatly expanding candidates. A study commissioned by the company has reveled that people in the proposed weight range who have the band have “statistically significant decreases in all measures of weight loss,” although the long-term effects of the band remain uncertain. The FDA acknowledged the results of Allergan’s study Wednesday, but doctors and medical experts cautioned about using the surgery too widely. The Lap-Band procedure was originally intended for people who were severely obese and had medical problems as a result, and was considered a last resort.