The war on obesity will not be won by reducing food intake alone, say researchers from the University of Colorado School of Medicine.
In a new article , published in the journal Circulation, James O. Hill, Ph.D., and colleagues say that helping people maintain an ideal body weight involves shifting the message from Eat Less, Move More” to Move More, Eat Smarter. This includes focusing on energy balance, which consists of three componentsfood intake, energy expenditure (physical activity and metabolism) and energy storage (as muscle or fat).
The basics of energy balance are common sense. If you eat more food than you burn off, you will gain weight60 to 80 percent of which will be in the form of fat. The body is best at maintaining energy balance at high levels of physical activity. This is how our lives were before our current sedentary lifestyleslike sitting  at desks, in cars , and in front of televisions.
The easiest way to maintain an ideal body weight, then, is to increase your physical activity. This pushes your body into the most efficient zone for maintaining energy balance.
Its not enough to work out more, though. You need to eat smarter to match your actual energy expenditure. This involves eating smaller portion sizes of food and reducing the energy densitythink fruit and vegetables instead of jelly donuts.
The researchers also point out that the body is more resistant to weight loss, which means that preventing weight gain will be easier than shedding the pounds. This can easily be done with small changes in physical activity and food intakesuch as walking 2,000 more steps a day and cutting out 100 calories a day (less than a can of soda).