All the fad diets and all the workouts in the world cannot erase this cold, hard fact: consuming too many calories will cause you to gain weight.
But are there foods and drinks that have zero or negative calories?
“The concept of these so-called zero or negative calorie foods is that you’ll burn more calories in digesting them,” in essence, cancelling them out, according to Tara Miller, a holistic nutritionist in Toronto. “But it’s not as simple a process as ingesting 10 calories and then burning them off because everyone metabolizes and burns things at different rates. I would never tell anyone to hold on to that thought for the purpose of being healthy.”
The going attitude is that foods like celery, cucumbers, lettuce, onions and some citrus fruits, which contain a lot of water and fibre, have zero or negative calories because the body burns them off in digestion and through elimination. But that’s not how the body works.
Basal metabolic rate (BMR), or the rate at which the body burns calories at rest, is based on age, height, weight and activity level. So, by definition, a person who is young, healthy and highly active will naturally burn more calories at rest. But the amount of energy burned in chewing and digesting food accounts for the least amount of BMR, roughly five to 15 per cent. Even if someone is extremely active, they wouldn’t burn many calories in doing this. And it would require eating a lot of lettuce and cucumbers in order to fill up, so you’d still be consuming more calories than you’re naturally burning.
“You also have to consider that not all calories are created equally,” Miller says. “If you were to eat 10 calories of fat versus 10 calories of sugar, your body is going to do different things with those calories.”
There’s nothing wrong with incorporating these foods into your diet, as they’re full of nutrients and vitamins that make up a healthy profile, but relying on them solely for the purpose of losing weight isn’t just misguided, it’s also counterintuitive.
“If we’re not eating enough calories, our body starts to lower our metabolism in order to stay alive and functional. So, we won’t burn more calories if we’re not eating calories; in fact, our body will store them,” Miller says.
The one way that these so-called zero calorie foods could help you in your weight loss journey is by filling you up thanks to their fibre load, thus keeping you satiated longer and preventing you from reaching for unhealthy options.
But nutrition experts warn of packaged foods and drinks that claim to have no calories, as the chemical and artificial ingredient load could actually cause you to eat more. A 2017 study out of the University of Manitoba found that artificial sweeteners used in diet soda, like aspartame, sucralose and stevioside, could be associated with weight gain and increased BMI.
“People consume artificial sweeteners and diet beverages and think they can eat cake,” Dr. Meghan Azad, a University of Manitoba professor and the study’s lead author, told Global News. “They’re shifting calories to other foods.”
Miller says the same applies when you deny yourself the foods you really want and instead binge on things that are perceived as healthier by comparison.
“I tell my clients to practice intuitive eating: If someone craves chips and they eat rice cakes instead because they think they’re lighter, they’ll often end up eating an entire bag of rice cakes. They lack flavour and satisfaction [and could lead you to continue eating]. You can’t fake out your body; it’s smarter than that. You’re better off just having a handful of chips and moving on.”
—With files from Carmen Chai