What is a calorie? Calories measure the energy contribution of food. Macronutrients (carbs, protein, fats) provide energy (calories), whereas water and micronutrients (vitamins, minerals) do not.
Many people rely on calorie-counting as a weight-loss tool, especially with the help of modern calorie-counting apps, including favorites such as “MyFitnessPal” and “LoseIt!” Despite multitudinous fad diets, the adage prevails that weight loss boils down to calories in versus calories out … yet some nutritionists believe that it is not the amount of calories that matter, but rather where they come from.
If you do find yourself in the calorie-counting camp, beware of these 5 common misconceptions.
When attempting weight loss, we are often advised to create a calorie deficit. Consuming too few calories, however, can backfire. If your body has sufficient fuel, it will burn fat reserves faster, whereas if you dip below a certain level of energy intake required for your body to biologically function on a basic level, your metabolism will temporarily slow down to conserve energy. We are wired to survive, so your body will adapt to expend fewer calories for each activity, preparing for what it believes to be impending starvation. Furthermore, your body will begin to break down muscle tissue for energy — and lean muscle mass increases metabolism. You will lose muscle mass, water, and bone, and regain lost weight more quickly.
The threshold at which metabolism slows is debated, but cited as approximately 1200 calories per day for women and 1800 calories per day for men (though it varies individually, so consult a registered dietitian). According to Brian Wansink, director of the Cornell University Food and Brand Lab and author of Mindless Eating, one can safely lose a half-pound per week without slowing down metabolism. Small changes can produce a big (and longer-lasting) effect. Dr. Wansink recommends cutting 100-200 calories a day — what he refers to as the “mindless margin” — a difference that we will not notice or miss, and which will not leave us feeling deprived. This may seem like a small change, but cutting 100 calories a day for a whole year could lead to a weight loss of 10 pounds. Eliminating one 240-calorie soda or candy bar daily could lead to a weight loss of 25 pounds per year.
Insufficient energy intake may also lead to fatigue, reduced bone mass, increased risk of osteoporosis, cold sensitivity, fertility problems, and psychosocial issues. Furthermore, drastically cutting calories can seriously endanger your heart, and rapid weight loss increases the risk of developing gallstones. Food stokes your metabolic rate, so feed your “fire” appropriately.
Your body will store extra calories as fat if you consume more calories than you expend — no matter what time of day. Diet plans often advise us to “stop eating after 7:00 p.m.” — rules like this can certainly support weight loss, as deadlines help curtail mindless snacking and emotional eating. Curbing late-night eating can also promote improved sleep, as digestion will not be inhibiting your sleep, and sufficient sleep aids weight loss efforts. So cutting back on late-night eating may very well enhance weight loss — but a calorie is a calorie no matter what time of day. Even if you may be less physically active at night (or not…), your metabolism does not shut off after dark.
While certain low calorie foods are nutrient-dense (fruits and vegetables), others lack these health benefits and may be highly processed with added sugar, starch, sodium, additives, fillers, and synthetic ingredients to compensate for flavor and texture. Furthermore, low-calorie or low-fat labels often allow us to feel like we can eat more, whereas maybe we would be more discerning in terms of portion control if eating the “real thing.”
Additionally, while the jury is still out on this one, it has been argued that diet sodas/artificial sweeteners can hinder weight loss efforts and may even be associated with weight gain.
Dieters love to believe that certain foods burn calories. You may have heard that grapefruit and celery are examples of such “negative calorie foods.” Who wouldn’t love to believe this?? Unfortunately, there is insufficient evidence to support this notion. Yes, we expend energy digesting, absorbing, and metabolizing our food — 10 to 15% of our daily energy expenditure is due to the thermic effect of food — in other words, energy we expend to process the food we consume. The thermic effect of protein is a bit higher (20-30%). Celery, for instance, contains insoluble fiber, which we cannot digest and therefore cannot convert to energy. Therefore, some part of fibrous foods may not “count.” Grapefruit and celery can be good choices when minding calories, as they are low calorie, nutrient dense, and full of dietary fiber. However, eating these so-called “negative calorie foods” does not create an energy deficit. But that doesn’t mean you should skip the produce aisle!
Don’t fixate on a particular number. Counting calories is never going to be 100% accurate. First, we tend to underestimate our energy intake and portion sizes. According to Dr. Wansink, “At high levels, all of us — normal weight and overweight alike — underestimate calorie levels with mathematical predictability.” Through his studies at the Cornell University Food and Brand Lab, Dr. Wansink found that “The more people had eaten, the less accurate they were. Someone eating a small, 300-calorie hamburger and a salad would underestimate the calories by about 10%, but someone eating a 900-calorie monsterburger would underestimate it by a whopping 40%. It didn’t matter whether the person was skinny or huge, male or female — the bigger the meal, the less they thought they ate.” Second, even if we measure portion size correctly, it is difficult to account for all of the ingredients used in a meal, particularly when dining out. Third, the calorie counts on nutrition labels are a rough estimate and our bodies digest and absorb food differently. As Dr. Marion Nestle says, “If a food looks like it should have more calories than is stated on the label, it probably does.”
The conclusion here is not to abandon counting calories — in fact, food journaling (whether or not it includes tracking calories) can be an effective weight loss tool, and I encourage all of my clients to track food intake when possible. Research has demonstrated that individuals who maintained a food journal lost nearly double the weight of individuals who did not. However, calorie-counting should be used as a guideline — a tool for increasing awareness of what goes into our mouths and a means of helping us maintain balance. Rather than fixating on a specific calorie goal, focus on consuming unprocessed, whole foods. As Michael Pollan says in In Defense Of Food, “Eat food. Not too much. Mostly plants.”