Top four reasons why diets fail 

 Washington: Losing weight is one of the top resolutions made each year, yet only 20 percent of people are able to achieve successful weight-loss and maintenance.

Now, Jessica Bartfield, MD, internal medicine who specializes in nutrition and weight management at the Loyola Center for Metabolic Surgery and Bariatric Care, has revealed the top four reasons why many dieters fail to lose weight.

Firstly, she said, that most people underestimated the amount of calories that they consumed per day. Food eaten outside their home tended to be much larger portion sizes and much higher in calories.

Next, she said, that typically people needed to cut 500 calories per day to lose 1 pound per week, which was very difficult to achieve through exercise alone, so it required about 60 minutes or more of vigorous activity every day.

Another reason as to why the dieters failed to lose weight was that people needed a steady stream of glucose throughout the day to maintain optimal energy and to prevent metabolism from slowing down, which they didn’t do.

Finally, she said, people who slept for less than six hours had higher levels of ghrelin - a hormone that stimulates appetite, particularly for high- carbohydrate/high- calorie foods. In addition, it also raised levels of cortisol, a stress hormone that could lead to weight gain.