The New Weight-Loss Math

What you don’t know about calories can hurt you. Here’s what you need to know to get the body you want.

By Matthew Kadey, MS, RD | September 27, 2016

You may have noticed that calorie counts are everywhere: Stamped on packaged foods, plastered on restaurant menu boards and found alongside cookbook recipes. And if you’re a health-conscious eater, chances are you pay a great deal of attention to these numbers in the name of cleaner, calorie-controlled eating. But what may shock you is that research shows calorie counting when it comes to dieting is at best overrated and at worst highly misleading. 

You see, calorie stats are based on a century-old formula called the Atwater system, in which the macronutrient components — carbohydrate, fat and protein — of a food have a set number of calories (a unit of energy). Carbohydrates and protein have four calories in each gram and fat contains a more lofty nine calories. So if a food has 8 grams of fat, 3 grams of protein and 7 grams of carbohydrate, theoretically it should deliver 112 calories to whoever eats it. But this fails to tell the whole picture when it comes to the calories your body actually extract from foods. Why? Because not all calories are created equal. 

The number of calories listed on a food label or fitness app can be very different from what you end up absorbing. That’s because the net amount of calories you obtain from your meals and snacks is heavily influenced by a number of factors. It turns out instead of counting calories you need to focus on eating more of the right kinds of foods so fewer calories are absorbed and you have a better chance of being leaner. That’s why it’s vital to take a look at the most recent research when it comes to calories and learn how to hack the science to keep you on track for physique greatness.

Protein Power

There is one very good reason why diets higher in protein have been shown to make it easier for you to hold onto your abs: Protein-rich foods make your metabolism burn hottest.

A big shortfall of the Atwater system for estimating the calories in food is that it fails to take into account the thermic effect of feeding. Think of TEF as the energy cost of chewing, digesting, absorbing, transporting and storing the food you eat. It turns out that protein has a significantly higher TEF than carbohydrates and fat. The TEF of protein ranges from 20 to 35 percent, whereas it costs us only about five to 10 percent of the energy consumed from carbohydrates or fats to digest and process them. In a study of people on a high-calorie diet, those who got 25 percent of calories from protein burned 227 more a day (and packed on more muscle) than those who only ate five percent of calories from protein. 

In other words, researchers at Tufts University determined that over a period of 16 to 24 years those who ate more protein at the expense of carbohydrates tended to pack on less weight. Protein contains nitrogen, which must be stripped off and eliminated by the liver and this extra metabolic step as well as other differences between the macronutrients is why the body requires more energy to handle protein. So even though carbs and protein have the same calories per gram (four calories in a gram), you net fewer of them from the latter.

Take Action: Owing to the abundance of protein, the true calorie count of a chicken breast, slab of beef or a bowl of Greek yogurt is likely lower than as advertised on the label. For this reason, you want to make sure that each of your meals and snacks includes plenty of protein at the expense of some carb and fat calories to reap the rewards of this calorie-burning (and muscle-making!) advantage. And continue to blitz whey protein, which has a particularly high TEF according to a 2011 American Journal of Clinical Nutrition study, into your postworkout shakes. Besides, protein is satiating, so you’ll be satisfied on less. Glazed doughnut? Not so much!

Go Nuts

Modern research shows that when it comes to eating with the purpose of zapping ab flab, you would be well served to eat closer to Mother Nature to benefit from some notable calorie savings, and there’s no better place to start than with whole nuts. A study published in the American Journal of Clinical Nutrition determined that a one-ounce serving of almonds provides the human body with about 129 calories, which is about 22 percent fewer than the 167 calories determined by the Atwater system and what is currently shown on nutrition labels. A similar study conducted on pistachios and published in the British Journal of Nutrition found that nuts may contain up to six percent fewer calories than previously measured. And walnuts have been found to deliver 21 percent less energy to the body than once thought.

Strong cell membranes of plant foods like nuts may lock in some of their macronutrients, including fat, thereby preventing them and the energy they provide from being fully absorbed through the digestive tract. So although a handful of walnuts may contain 15 grams of fat, which translates into 135 calories, it’s likely not all of these fat calories are being absorbed. These fascinating results could help explain the results from studies showing that nut eaters are less likely develop a round belly. On the flipside, we may absorb more calories from a food when its cell walls have been broken down through processing. So peanut butter could very well provide more digestible calories than do whole peanuts.

Take Action: As with whole nuts, we may also absorb fewer calories from other foods like legumes, seeds, whole grains and vegetables consumed in their least processed states. Processing such as juicing fruits and milling grains ruptures cell walls and in the process reducing the energy needed for digestion. So to help in the battle of the bulge, more often try eating almonds instead of almond butter, apples instead of applesauce, wheat berries instead of whole-wheat spaghetti or whole-wheat flour, oranges instead of orange juice and cacao nibs instead of chocolate bars. Grinding meat into hamburger also may increase calorie absorption by making things easier for your digestive system, so consider steaks over burgers for a protein fix.

Reign of Whole Grain

One of the most prevalent weight-loss myths is that all calories are essentially the same. Take in too many of any calories and you’ll punch your ticket to pudgeville. But we now know that some calories work harder to keep your physique in tip-top shape. Case in point: A study in the journal Food & Nutrition Research provided volunteers either a sandwich made with multigrain bread and cheddar cheese or one made with highly processed white bread and cheese slices. Even though both meals had the same amount of total calories on paper, the less-processed sandwich meal required nearly twice as much energy to digest resulting in fewer calories being available to the body for storage. The processed sandwich used only 11 percent of the food’s calories for the needs of digestion, but the multigrain sandwich used almost 20 percent. So calorie counters take note: This is a good example of how nutrition trumps numbers tallying when it comes to winning the battle of the bulge.

Take Action: Again, this is proof that it’s harder for your digestive system to break down foods that are closer to their natural state, which can translate into calorie savings and making it easier for you to knock a few inches off your waistline. In other words, give your digestive system a bigger workout by shunning processed items like white rice for their more natural counterparts like brown rice. Not to mention eating more fiber-rich whole foods like vegetables, beans and whole grains will keep you feeling full and satisfied, most likely reducing your total calorie consumption while simultaneously increasing the nutrient density of your diet.

Bug Love

When you bite into your lunch sandwich you aren’t the only one feasting on it. Our guts are teeming with trillions of bacteria that also rely on this nourishment. And emerging research suggests various types of bacteria in your digestive tract help your body absorb calories from food. That means if there is a robust population of the type of bacteria that breaks down food into energy, you may be soaking up more calories from the food you eat. So the makeup of your microbiome could play a vital role in the overall calorie cost of your diet and, in turn, weight management by making you more or less prone to absorbing and storing extra calories.

Take Action: Consider splurging for organic meats and dairy more often. It looks like the millions of pounds of antibiotics used in conventional livestock production each year can skew the population of bugs in your gut, nurturing those that are more efficient at pulling calories from food and transporting them into your system. Beyond eating antibiotic-free steak and milk and not taking antibiotics for every cough you have, load up on high-fiber vegetables, fruits and whole grains since fiber can help foster a population of microbes that are less efficient at extracting energy from food. And in terms of your waistline, that is a good thing.

Raw Power

It’s not necessary for you to completely eschew your oven when trying to shed some weight, but it might be a good idea to nosh on raw foods more often.

A watershed study by Harvard scientists in the Proceedings of the National Academy of Sciences showed that cooking actually increases the amount of calories our bodies absorb from food. The study authors believe that cooking performs some of the digestive process for us such as denaturing proteins and gelatinizing starches, meaning that our bodies don’t expend as much energy dealing with digestion and thereby allowing more calories to be available. Further, larger quantities of raw food require more laborious chewing, which expends additional energy and also encourages satiety. So the total amount of calories we glean from raw carrots or raw fish (yum, sushi!) could very well be less than from the same portion of roasted carrots or fish sticks. And a medium-rare steak could very well deliver less energy to the body than a well-done piece of beef since its muscle fibers might be more tightly wound as a result of a shorter cooking time and, in turn, requiring extra work for your digestive system to untangle.

Take Action: Back in the day, putting meat to fire allowed our ancestors to obtain more energy to develop bigger brains, but now eating too many cooked processed foods are giving modern humans bigger guts. After all, punching computer keys all day requires less energy than that required to take down woolly mammoths. So tap into the fat-frying power of raw foods by working them into your daily menu. This can be accomplished by tossing a handful of raw sunflower seeds or nuts into breakfast oatmeal, snacking on raw baby carrots or raw fruits like pears, serving a raw salad at every dinner meal and even experimenting with recipes for ceviche, a raw seafood dish. Cooking root vegetables increases their levels of absorbable carbohydrates from the intestines, so why not try working shredded raw beets or turnips into salads instead of sending them to the fire. And if you eat pasta, enjoy it al dente to give your digestive tract more of a workout.

Rock Solid

When it comes to the calories you consume each and every day, form matters. A study in the journal Obesity exposed people to the same number of calories in liquid or solid form only to find that post-meal hunger and desire to eat were greater when subjects consumed liquid calories. It appears that a solid meal leads to a greater drop in levels of the hunger-inducing hormone ghrelin, which could help tame your appetite. Similarly, the fibrous structure in whole fruit helps slow the absorption of its naturally occurring sugars, which can contribute to satiety. The takeaway is that the body doesn’t register 300 liquid calories in the same way it does if those 300 calories came in the form of whole food which could lead to increased hunger and higher overall daily calorie intake. Hence, one reason for the strong association between soda intake and weight gain.

Take Action: While your postworkout protein shake won’t derail your diet, be careful not to become too chummy with your blender. Overall, you want most of your daily calories to come in the form of solid food. (Beverage intake accounts for up to 20 percent of calories in the typical American diet.) That means bidding adieu to orange juice in favor of a whole orange, opting for a kale salad instead of green juice and saying sayonara to sweetened drinks like soda for calorie-free options like water or tea. And when you do whip up smoothies, make them so they stick to a spoon. A Dutch study discovered that a thick milkshake lead to greater feelings of fullness than a thinner version despite containing only one-fifth of the calories. For this reason, a bowl of yogurt is likely to quell your hunger more than a glass of milk.

Watch the Clock

When you consume your calories might matter as much as how many you take in. When Italian researchers looked at the eating habits of more than 1,200 adults they discovered that the risk of being obese was greatly increased for study participants who consumed half or more of their daily calories at dinner. Along the same lines, a study in the journal Obesity discovered that volunteers who consumed more calories at breakfast at the expense of calories later in the day (700 calories at breakfast, 500 at lunch, 200 at dinner) experienced greater fat loss around their waistlines than those who took in substantially more calories at dinner than breakfast (200 calories at breakfast, 500 at lunch, 700 at dinner). And Spanish scientists showed that when people ate lunch after 4:30 p.m., they burned fewer calories while resting and digesting their food than they did when they took in their meal at 1 p.m. — even though the calories eaten and level of activity was the same.

It could be that we burn more calories earlier in the day when our metabolisms are higher, while later noshes are more likely to go into fat storage. Insulin sensitivity may also fall as the day progress, so there is a greater chance that the carbohydrates consumed will get stocked away in fat stores. What all this means is that when it comes to fending off the flab monster a calorie consumed at daybreak may not be the same as a calorie eaten after sunset. Late-night calories are more prone to be stored as body fat.

Take Action: This research shows it might be a good idea to follow this sage advice: “Eat breakfast like a king, lunch like a prince and dinner like a pauper.” If you are struggling to keep your beach body, consider making your morning repast more substantial and then tapering down calorie intake as the day progresses. Besides, a substantial breakfast can also work to promote satiety early in the day and lessen the risk for mindless snacking later in the day.



About the Author

Matthew Kadey, MS, RD

Matthew Kadey, M.S., RD, is a Canadian-based dietitian, nutrition writer and recipe developer. A regular contributor for Oxygen and Muscle & Performance magazines, he is also the author of Rocket Fuel: Power-Packed Foods for Sports and Adventure (VeloPress, 2016), Muffin Tin Chef (Ulysses Press, 2012) and The No-Cook, No-Bake Cookbook (Ulysses Press, 2013). An avid cycle tourist, Matthew has pedaled his bike through Thailand, Cuba, New Zealand, Sri Lanka and Myanmar.