For decades doctors have preached that eating too much saturated fat can lead to heart disease and obesity, and studies have consistently backed this up. So the biggest fear of many health professionals is that a diet of steak, eggs, and butter might increase the buildup of plaque in the arteries, which causes heart attacks and strokes. The limited number of short-term studies (the longest, a year) have not shown the Atkins diet to affect cholesterol adversely. But...again, the long-term effects are impossible to forecast. The authors of these studies and other experts in the field are quick to point out that any weight loss will cause a person's "bad" cholesterol levels to fall. They also caution that anyone trying this diet should reduce fat intake—especially saturated fat—once the maintenance phase begins; otherwise it's easy to regain what you lost and put yourself at increased risk of heart disease.