Studies have shown that people who keep daily diet records are far more successful at losing weight than people who don't keep track of what they eat. Researchers believe that many weight-loss efforts fail because people eat more calories than they intend to consume. One study followed a group of patients who reported that they could not lose weight when consuming only 1,200 calories a day. The study found that the group consumed, on average, 47% more than it claimed and exercised 51% less. In contrast, when dieters record what they eat, their actual consumption more closely matches their reported consumption.