Rather than focus on losing weight, you should be trying to gain muscle in order to improve your overall health. Learn why losing fat is a misguided goal and how you should approach weight loss in a different way.
Are you shedding fat or just losing weight?
The types of fuel you ingest enter into different metabolic pathways in order to be broken down safely. There’s a “downstream” reaction for each different type of nutrient, with varying degrees of effects on our health. Some promote health and leanness while others cause inflammation, form triglycerides, damage hormone receptors, and cause you to get out of shape.
Even intuitively, we understand that one hundred calories from an apple will affect our body differently than one hundred calories from a chocolate bar. A chocolate bar has a higher glycemic index, meaning it raises blood sugar higher and requires more insulin to control. If you’re diabetic, you’re aware of this effect — eating low GI foods can help you better control over your blood sugar and manage diabetes,
The notion that “a calorie is not a calorie” was recently tested  by researchers at Boston Children’s Hospital, led by Dr. David Ludwig.
The researchers fed their subjects diets with the same amount of calories — however, some diets were higher in carbohydrates and some diets were higher in fats. The people who ate a diet lower in carbohydrates ended up effortlessly expending more calories than those on a low-fat diet. Subjects on the low-fat diet needed to exercise for an hour a day to match the calories expended by those on the low-carbohydrate diet.
If you’re overweight, it is important to lose weight. However, not all weight loss is created equal. It’s better to lose pounds from fat than from muscle. You can be thin and unhealthy — your body composition makes a difference.
In fact, your muscle-to-fat ratio is one of the most important measurements of your health.
Having more muscle on your body is healthier for a number of reasons. More muscle helps in glucose uptake, which helps your body manage its blood sugar. One study found that muscle mass is inversely correlated with insulin resistance. Added muscle can also raise our basal metabolic rate. 
Consider the long-term study of postmenopausal women conducted by the Women’s Health Initiative.  Over seven years, the average weight lost on a low-fat diet was only one pound. At the same time, the average waist circumference — one way to measure belly fat — increased. This suggests that the subjects didn’t only fail to lose body fat, but may have gained more fat than they lost muscle.
Building and Preserving Lean Muscle
If you could embark on one of two diets, one that burned more fat and one that burned more muscle, which would you choose? Most people would choose the fat-burning diet — the one that improves body composition without compromising lean muscle tissue. That should be the fitness goal of any diet plan.