BOSTON (AP) — When it comes to losing weight, it turns out the simple math of counting calories doesn’t always add up.
Fad diets come and go, but the underlying message almost always follows a simple equation. If you consume fewer calories than you burn, the weight will melt away.
In principle, it’s true. And counting calories can be a useful tool for managing weight. But it only works if you know what numbers you’re counting. And what’s been billed as basic math can sometimes look more like Einstein’s theory of relativity.
That’s because a complex web of factors influences how or even if our bodies process calories. And it turns out diet quality is just as important as quantity, and possibly more.
“Different foods have very different effects on the brain, liver, fat cells, muscle function, pancreas and all organs related to metabolism and body weight,” said Dr. Dariush Mozaffarian, a cardiologist and director of the Food is Medicine Institute at Tufts University.
A calorie is the unit of energy used to count what the body can get from carbohydrates, proteins and fats. That sounds simple, but the complexity of counting calories went mainstream recently, when a lawsuit accused the maker of David protein bars of affixing labels that misrepresent how many calories and how much fat the products contain. The lawsuit has since been dropped.
The allegations were based on an analysis of the bars using bomb calorimetry, which measures calories by burning food and calculating the amount of heat released, a method that counts every potential calorie. But our bodies aren’t combustion chambers and don’t treat all calories the same. The company’s numbers, like many food labels, are based only on the calories our bodies can actually use. Technically, both are correct, but only the latter matters for diet.
“You could put sawdust into a bomb calorimeter and you would get basically 4 calories per gram,” said Dr. David Ludwig, an endocrinologist and researcher at Boston Children’s Hospital. “If you’re a termite, yes, you’ll get calories from it. But humans won’t.”
The calorie counts on most nutrition labels reflect the total our bodies are likely to metabolize, not their burn rate. But they still can be misleading. Because of permitted rounding, the tallies can be off by as much as 20%. Additionally, the digestibility of an ingredient, whether and how it is cooked, to what extent it was processed, variations in processing, even quirks in our own DNA — all of these things influence whether and how our bodies use the calories we eat. Even that is just the start of the complications.
Our bodies determine how to process calories — either burning them or storing them — depending in part on our energy needs. But the quality of the calories matters, too. High-glycemic foods, such as white breads, pastas and sugars, are easily converted to usable energy and trigger our bodies to store calories, Ludwig said.
Foods containing resistant starches, including some beans, whole grains and seeds, resist easy conversion into usable energy and don’t trigger that same storage response. They also are more difficult to process, so we absorb fewer of the total calories contained in them.
“Having a snack of 8 ounces of sugary beverage, 100 calories, should be better for your weight than 1 ounce of nuts at 200 calories, right?” Ludwig said. “That’s the opposite of what actually happens because those 100 calories, even if they’re fewer at that moment, they shift your body toward storing fat and leave you hungrier sooner.”
Which of course triggers you to eat more, well, calories.
Even cooking and ripeness influence the equation. The calories in cooked foods are more easily absorbed than from raw ingredients, while the calories in unripe produce, such as bananas, are less easily absorbed. This means the number of calories you get from eating a medium banana, which is listed at 105 calories, can depend on how ripe it is.
As for processing, including something as simple as grinding a food, can change caloric impact.
“One classic example is that the calories in whole almonds are absorbed substantially less well than the calories in almond butter,” Ludwig said. “Just processing the almonds into almond butter causes a change in how much they will be absorbed.”
Ultra-processed foods introduce another challenge. Diets high in such foods have been found to decrease the number of calories we burn at rest, Mozaffarian said. That means a higher proportion of those calories will stick to your ribs.
Then there’s just plain old variation between people. Genetics lead our bodies to treat calories differently, said Dr. Fatima Cody Stanford, a Harvard Medical School obesity specialist. Even something as simple as a bad night’s sleep can change how the body processes calories. So you might absorb more or fewer calories from the same food on different days.
So what’s a weight watcher to do? Calorie counts can be a rough guideline; many people otherwise struggle to make healthy choices or determine appropriate portions, Ludwig said.
But the evidence indicates people should focus on diet quality, not just calorie quantity. Avoid ultra-processed foods, particularly refined starches, and build your diet around whole, minimally processed foods with an emphasis on plant-based ingredients rich in fiber.
“We need to think about calories in a much more sophisticated fashion than the number on the package,” Ludwig said. “The number on the package can do more harm than good by misleading people into thinking that it’s simply an accounting problem.”
J.M. Hirsch is a food and travel journalist and the former food editor for The Associated Press.
FILE - A customer shops at a Grocery Outlet store in Pleasanton, Calif., on Sept. 15, 2022. (AP Photo/Terry Chea, File)
FILE - A customer looks at items at a Grocery Outlet store in Pleasanton, Calif.,. on Sept. 15, 2022. (AP Photo/Terry Chea, File)
ANKARA, Turkey (AP) — President Donald Trump arrived in Ankara Tuesday afternoon for the NATO summit, as the transatlantic military alliance was announcing billions in arms deals in an attempt to appease the mercurial U.S. leader.
Trump was expected to head first to the presidential compound of Turkish leader Recep Tayyip Erdoğan, a close ally who is hosting this year’s gathering.
Just before Air Force One touched down in Ankara, NATO showcased a series of military projects worth billions of dollars — an investment that the alliance's secretary-general, Mark Rutte, called “money well spent.” An energized Rutte was speaking to government ministers and defense industry officials at a forum billed as NATO’s “big reveal,” to the thrum of techno music and a slick video display.
NATO as an organization does not own any weapons — these are the property of the 32 member countries — but it does have a fleet of 14 AWACS early warning radar surveillance planes that are about 50 years old, along with some newer surveillance drones.
A deal to replace the aging planes was announced Tuesday. Swedish manufacturer Saab will be supplying up to 10 new GlobalEye surveillance aircraft for a 10-nation consortium, Swedish Prime Minister Ulf Kristersson announced.
“It’s a moment of great pride,” he said, noting that the twin-engine aircraft would be “made within the alliance for all the alliance.”
Some of the projects will be paid for with funds from a system of cheap loans for defense purposes set up by the European Union, comprising up to $170 billion raised on capital markets.
“We need to ensure that we are translating our economic might into military capabilities, putting the cash to work from defense plans to drones, from money to missiles and interceptors,” Rutte said.
Trump has branded NATO a “paper tiger” that would cease to function without American arms and leadership. At the forum on Tuesday, Michael Duffy, a U.S. undersecretary of defense, said “the reality is that we need production increases across the board.”
“We will be looking to increase our exports to those who are looking to buy our equipment, and we’ll also be looking to partner with the expansion of production capacity here in Europe,” he said.
Representatives from 15 nations shook hands and patted shoulders on a vast podium under the NATO logo as they announced a multinational effort to buy air-to-air refueling and transport planes from Airbus.
Then Rutte announced a four-country effort to purchase as many as five new Triton surveillance drones to add to NATO’s small fleet.
“It is genuinely made in NATO, and creating jobs on both sides of the Atlantic,” he said.
Rutte told reporters on the eve of the military alliance’s two-day summit in Turkey that “we will announce tens of billions in new contracts that will provide the crucial kit we need to deter and defend.”
However, at Tuesday's event, no dollar figures were given and the display included some projects long since agreed.
The defense industry splash comes a few weeks after Rutte tried to ease U.S. concerns about military spending at NATO with a new pitch using a chart labeled “The Trump Trillion” — showing $1.2 trillion in spending by European allies and Canada since 2017.
Far from being impressed, Trump appeared unmoved, saying he was still disappointed at some NATO allies’ refusal to join the Iran war, which he had launched alongside Israel without consulting them.
“We don’t need their money — we don’t need anything,” Trump said. “I just want loyalty.”
The summit is being held in President Recep Tayyip Erdogan’s sprawling palace compound in Ankara, and Trump has suggested he would come bearing gifts for the Turkish leader.
Speaking Monday on the morning show “Fox & Friends,” Israeli Prime Minister Benjamin Netanyahu urged the U.S. not to sell F-35 fighter jets to Turkey, saying that Erdogan “calls openly for the annihilation of Israel.”
Turkey and Israel have acrimonious relations. Erdogan frequently accuses Israel of committing genocide in its war in Gaza, triggered by the deadly Oct. 7, 2023, Hamas-led attack on southern Israel.
Turkey was barred from the F-35 program in 2019 after it purchased Russian-made S-400 missile defense systems. However, Trump, who has warm relations with Erdogan, has hinted ahead of his planned visit to Ankara that the sales could soon resume.
Netanyahu said selling Turkey F-35s would “upset the power balance in the Middle East, which is ultimately guaranteed by Israeli air superiority and also, I think, by America’s posture in the Middle East.”
Israel’s Air Force depends on hundreds of U.S. fighter jets, including F-35s, F-16s and F-15s.
Turkey beefed up security and banned protests in Ankara during the summit, but a small group of demonstrators gathered on Tuesday in the capital. They were quickly surrounded by police, and a legal association said 22 students affiliated with the leftist Turkish Workers Party and three lawyers had been detained.
The focus of the summit is a stronger Europe for a stronger NATO. The Trump administration has warned the allies that they must handle Europe’s security alone as the United States focuses on China and the Indo-Pacific region.
The Pentagon wants a reboot and is promoting what it calls “NATO 3.0,” a vision of the alliance in which Europe assumes greater responsibility for its own defense, freeing the U.S. to concentrate on other priorities.
But hiking defense spending means increasing taxes or diverting resources from other priorities. U.K. Defense Secretary John Healey unexpectedly quit last month, saying the British government was not willing to spend at a time of rising threats.
Concern is mounting among some northern and central eastern countries that Russia might be preparing a hybrid attack — a combination of conventional warfare with tactics like cyberattacks — on the continent as Russian President Vladimir Putin struggles to secure victory in Ukraine.
Keir Starmer’s office said the British leader will be “focused on building a stronger and more European NATO” on what is likely to be his last foreign trip as prime minister.
Starmer, who announced his resignation June 22, has faced criticism from military leaders, opposition politicians and some in his center-left party for the slow rate of increase in U.K. military spending.
His government has committed to reach the NATO budget target of spending 3.5% of gross domestic product on defense by 2035 but does not have a concrete plan to get there. Its current spending plan will see that spending hit 2.7% of GDP by 2029.
Associated Press writers Jill Lawless in London and Andy Wilks in Istanbul contributed to this report.
President Donald Trump walks with Turkish President Recep Tayyip Erdogan, left, upon arriving for the NATO summit in Ankara, Turkey, Tuesday, July 7, 2026. (AP Photo/Alex Brandon)
Participants view displays during the NATO Defense Industry Forum at the NATO summit in Ankara, Turkey, Tuesday, July 7, 2026. (AP Photo/Hussein Malla)
From left, NATO Secretary General Mark Rutte, President and CEO of Saab Micael Johansson and Sweden's Prime Minister Ulf Kristersson during the NATO Defense Industry Forum at the NATO summit in Ankara, Turkey, Tuesday, July 7, 2026. (AP Photo/Hussein Malla)
NATO Secretary General Mark Rutte, left, speaks with U.S. Under Secretary of Defense for Acquisition and Sustainment Michael Duffey during the NATO Defense Industry Forum at the NATO summit in Ankara, Turkey, Tuesday, July 7, 2026. (AP Photo/Hussein Malla)
Two men walk past the NATO logo during the NATO Defense Industry Forum at the NATO summit in Ankara, Turkey, Tuesday, July 7, 2026. (AP Photo/Hussein Malla)
NATO Secretary General Mark Rutte speaks during the opening of the NATO Defense Industry Forum on the sidelines of the NATO summit in Ankara, Turkey, Tuesday, July 7, 2026. (AP Photo/Hussein Malla)
NATO banners in front of the Bestepe National Mosque ahead of the NATO Summit in Ankara, Turkey, Monday, July 6, 2026. (AP Photo/Emrah Gurel)
NATO Secretary General Mark Rutte, left, meets with Turkish Presidential Defense Industries Directorate Haluk Gorgun as he arrives ahead of the NATO Summit in Ankara, Turkey, Monday, July 6, 2026. (Osmancan Gürdoğan, Pool Photo via AP)
NATO Secretary General Mark Rutte speaks during a media conference at the International Media Center ahead of the NATO Summit in Ankara, Turkey, Monday, July 6, 2026. (AP Photo/Hussein Malla)
Estonia's Prime Minister Kristen Michal, center left, walks with Turkish Culture and Tourism Minister Mehmet Nuri Ersoy, left, during airport arrivals ahead of the NATO Summit in Ankara, Turkey, Monday, July 6, 2026. (Metin Aktas, Pool Photo via AP)
A Turkish flag and NATO banners cover buildings ahead of the NATO Summit in Ankara, Turkey, Monday, July 6, 2026. (AP Photo/Hussein Malla)
