By Bob Sterner –
Stuff yourself like a Thanksgiving turkey and still lose weight. That’s the promise of foods with so-called negative calories, which supposedly burn more calories to digest than the foods provide.
Is it an empty promise? Probably.
Only about 5 to 10 percent of a person’s total energy expenditure goes towards digesting and storing nutrients in the foods they eat, according to the Mayo Clinic. Even foods that contain just a few calories still require some energy/calories to digest, so theoretically, there may be negative-calorie foods. Reputable scientific research has yet to identify any.
Ultimately, the bad news for those looking to shed pounds is that negative-calorie food diets do not work as advertised. The good news is that these foods can still help people lose weight because they reduce hunger by filling stomachs with foods that are not calorically dense, although these foods are not negative calories.
Foods promoted as negative calories typically include fruits and vegetables which are primarily water and carbohydrates with very little fat or protein. Healthline.com noted examples such as celery, lettuce, grapefruit, tomatoes, cucumbers and watermelon, all of which are at least 90 percent water.
In addition to high water content, many so-called negative-calorie foods are fiber rich. This is another boon for individuals looking to lose weight. NDTVfood.com explained that high fiber foods help shed pounds because they stay in the body longer, which offsets feelings of hunger. They also release sugar relatively slowly, reducing the ability of the related calories to turn into fat.
Beyond being low in calories, these foods can offer other benefits. Many are rich in vitamins and minerals. Lifegate.com noted foods such as cucumbers, cauliflower and papaya are rich in vitamin C. Tomatoes contain lycopene, which helps lower cholesterol and blood pressure. Asparagus has anti-inflammatory and diuretic nutrients. Besides fiber, celery is rich in sodium and potassium, which help muscles after workouts. Capsaicin in chili peppers also increases metabolic rate, which causes the body to burn more calories. Even coffee, at two calories per cup without sugar or milk, stimulates burning fat and reduces hunger cravings.
Be forewarned. Any positive dietary impact of these negative-calorie foods can be easily offset by how they’re served. Consider a baked potato. Naked, it is relatively harmless, HealthExcellence.com explained. But add a big pat of butter, sour cream and bacon bits and the damage is done. Similarly, dipping celery sticks and broccoli in ranch dressing may enhance their taste, but it unequivocally takes them off the low-calorie list.
The potential issues with these foods don’t stop with their preparation. Diets focused on extremely low- or negative-calorie foods bring other challenges. They can undermine basal metabolic rates that support basic body functions and harm an individual’s digestive systems and ability to metabolize foods. Beyond this, extremely low-calorie diets can lead to fatigue, reduce fertility, weaken bones and lower immunity levels, Healthline.com reports.
Working towards a healthy body weight is always a good idea. Seeking out the promise of negative-calorie foods is probably not. Those foods probably exist and going too low in calories may do more harm than good.