Complex sentence: Her overeating, compounded by a thyroid condition and slow metabolism, led to substantial weight gains, and in 1986, pelvic infections kept her bedridden for two years, during which she gained 150 pounds.
Split into simpler sentences: Her overeating, compounded by a thyroid condition and slow metabolism, led to obesity. In 1986, pelvic infections due to her weight problems kept her bedridden for two years, during which she gained an additional 150 pounds.