Are All Calories Equal?

Is losing weight a simple matter of cutting calories, or do you need to be choosier about the type of calories you eat? Anita Bean investigates.

- Anita Bean

You know the rules: eat fewer calories than you burn and you’ll lose weight; eat more and you’ll gain weight, right? Well, it may not be that simple. According to new research, the source of calories you eat may be more important than simply how many you eat.

In 2010, Mark Haub, professor of nutrition at Kansas State University shed 29 pounds in 10 weeks, eating Twinkies, Doritos, Oreos and other treats instead of normal meals. He didn’t do the experiment to endorse a junk food weight loss programme but to prove a point: calories are all that matter in weight loss. Haub’s body fat dropped from 33.4 to 24.9 per cent. This posed the question: what matters more for weight loss, the quantity or quality of calories? As cyclists eager to keep our weight under control, the answer clearly matters a great deal.

The question as to whether all calories are equal has been hotly debated by scientists for many years, and has proved to be a controversial topic. Some believe that a calorie is a calorie no matter where it comes from: to lose weight people simply need to eat less and move more. Others believe that no calories are alike and that provided you choose the source of your calories carefully, then you can lose weight without counting calories.

“There’s no doubt that energy (calorie) balance — represented as calories in versus calories out — matters when it comes to weight loss,” explains Dr James Betts, associate professor in nutrition and metabolism at the University of Bath. “Long-term changes in mass are generally proportionate over time to the net balance between energy in and out.” 

Indeed, studies using rigorous standards have consistently shown that when people create a calorie deficit, they lose weight. Conversely, when people eat more calories than they need, they gain weight.