If you’ve ever waited in line at a grocery store, then you’ve no doubt been subject to the purgatory that is the check-out lanes’ racks of tabloid and fitness magazines.
In addition to evaluating celebrities' beach bodies or speculating over a new romance, these magazines are notorious for marketing get-fit-quick schemes and crash diets. And perhaps no vegetable is so beloved by fad-dieters than celery.
While juicing celery may be the latest (unsubstantiated) craze, celery’s fitness origin story lies in the myth that it is a so-called “negative calorie” food. Have you ever heard you’d burn more calories than you’d consume by eating celery? Then you’ve been lied to.
Melissa Majumdar is a bariatric coordinator at Emory University Hospital Midtown and a spokesperson for the Academy of Nutrition and Dietetics. She tells Inverse that just like many other fad diets, consuming so-called negative calorie foods like celery is neither scientifically accurate nor advantageous in the long run.
Do negative calorie foods really exist?
It stems from the idea that your body expends small amounts of energy even when you’re not exercising — for example, just keeping your body sitting upright at your desk requires 60 to 130 per hour.
“... there are no negative-calorie foods.”
This myth suggests that moving your jaw to chew up celery and digesting it will burn more calories than the celery — or equivalent watery food — contains. This, however, is total nonsense, says Majumdar.
“Since all foods contain calories, there are no negative-calorie foods,” Majumdar explains.
While it is true that our bodies burn a little energy to consume our food, it’s nowhere near equalling out the calories in the food itself.
“The act of digesting and absorbing food accounts for about 10 percent of our calorie intake and is called the thermal effect of food (TEF),” Majumdar explains. “If metabolism is measured after eating, there is a small increase in metabolic rate because of the body working to turn the food into energy. TEF is influenced by what a person eats: larger meals require more calories to metabolize and different macronutrients metabolize differently.”
If someone ate 2000 calories, for example, their body would burn off 200 calories of that through digestion, Majumdar says. For a stalk of celery, which contains about 10 calories, the effect would be negligible.
This is supported by research as well, including a 2013 study in the journal Proceedings of the Nutrition Society that found celery did not create a negative energy balance in a cohort of 15 women.
What else is in celery?
Calories aren’t the only thing you should consider when creating your meals, Majumdar says.
Nutrient content and density are also important. Celery is a good source of vitamin C, potassium, and fiber — not to mention water — but there’s not much else going on inside its green interior. It lacks necessary macronutrients like fat, protein, and carbs.
“Meals should consist of foods from each food group to provide all the needed nutrients,” Majumdar says. “Calorie content alone should not be considered.”
And while you’re unlikely to overdo it on the water content of a handful of celery sticks, there is a real risk of water intoxication or “water poisoning” when consuming more than 1 liter of water per hour.
Despite what Hydro Flask influencers might tell you, there is such a thing as too much water — and if you’re guzzling the stuff all day long then you might want to consider more variation in the food you consume later on.
Why “negative calorie” foods aren’t a good weight loss plan
It should also be said that calories themselves are not inherently a bad word.
Our bodies literally need calories to do anything. Consuming a diet of only high-water content foods like celery, watermelon, or lettuce simply won’t get the job done.
“Foods that have a greater percentage of water, like fruits and vegetables, will be lower calorie, and therefore provide less energy,” Majumdar says.
And even though a calorie deficit (meaning you burn more calories through the day than you consume) is recommended for weight loss, she says that following diet myths like this are not the way to get there sustainably.
“For sustainable weight loss, I would discourage someone from choosing foods based on calories alone,” Majumdar says. “If the entire focus is on calorie intake and doesn't look at nutritional value, food preferences, food preparation, etc., it is not sustainable or healthy.”
CHECK, PLEASE is an Inverse series that uses biology, chemistry, and physics to debunk the biggest food myths and assumptions.