Millions of dieters give up when their calorie-counting is unsuccessful. Camacho was more stubborn than most. He took photos of his meals to record his intake more accurately, and would log into his calorie spreadsheets from his phone. He thought about every morsel he ate. And he bought a proliferation of gadgets to track his calorie output. But he still didn’t lose much weight.
One problem was that his sums were based on the idea that calorie counts are accurate. Food producers give impressively specific readings: a slice of Camacho’s favourite Domino’s double pepperoni pizza is supposedly 248 calories (not 247 nor 249). Yet the number of calories listed on food packets and menus are routinely wrong.
Susan Roberts, a nutritionist at Tufts University in Boston, has found that labels on American packaged foods miss their true calorie counts by an average of 8%. American government regulations allow such labels to understate calories by up to 20% (to ensure that consumers are not short-changed in terms of how much nutrition they receive). The information on some processed frozen foods misstates their calorific content by as much as 70%.
That isn’t the only problem. Calorie counts are based on how much heat a foodstuff gives off when it burns in an oven. But the human body is far more complex than an oven. When food is burned in a laboratory it surrenders its calories within seconds. By contrast, the real-life journey from dinner plate to toilet bowl takes on average about a day, but can range from eight to 80 hours depending on the person. A calorie of carbohydrate and a calorie of protein both have the same amount of stored energy, so they perform identically in an oven. But put those calories into real bodies and they behave quite differently. And we are still learning new insights: American researchers discovered last year that, for more than a century, we’ve been exaggerating by about 20% the number of calories we absorb from almonds.
The process of storing fat – the “weight” many people seek to lose – is influenced by dozens of other factors. Apart from calories, our genes, the trillions of bacteria that live in our gut, food preparation and sleep affect how we process food. Academic discussions of food and nutrition are littered with references to huge bodies of research that still need to be conducted. “No other field of science or medicine sees such a lack of rigorous studies,” says Tim Spector, a professor of genetic epidemiology at Kings College in London. “We can create synthetic DNA and clone animals but we still know incredibly little about the stuff that keeps us alive.” (...)
Our fixation with counting calories assumes both that all calories are equal and that all bodies respond to calories in identical ways: Camacho was told that, since he was a man, he needed 2,500 calories a day to maintain his weight. Yet a growing body of research shows that when different people consume the same meal, the impact on each person’s blood sugar and fat formation will vary according to their genes, lifestyles and unique mix of gut bacteria.
Research published this year showed that a certain set of genes is found more often in overweight people than in skinny ones, suggesting that some people have to work harder than others to stay thin (a fact that many of us already felt intuitively to be true). Differences in gut microbiomes can alter how people process food. A study of 800 Israelis in 2015 found that the rise in their blood-sugar levels varied by a factor of four in response to identical food.
Some people’s intestines are 50% longer than others: those with shorter ones absorb fewer calories, which means that they excrete more of the energy in food, putting on less weight.
The response of your own body may also change depending on when you eat. Lose weight and your body will try to regain it, slowing down your metabolism and even reducing the energy you spend on fidgeting and twitching your muscles. Even your eating and sleeping schedules can be important. Going without a full night’s sleep may spur your body to create more fatty tissue, which casts a grim light on Camacho’s years of early-morning exertion. You may put on more weight eating small amounts over 12-15 hours than eating the same food in three distinct meals over a shorter period.
There’s a further weakness in the calorie-counting system: the amount of energy we absorb from food depends on how we prepare it. Chopping and grinding food essentially does part of the work of digestion, making more calories available to your body by ripping apart cell walls before you eat it. That effect is magnified when you add heat: cooking increases the proportion of food digested in the stomach and small intestine, from 50% to 95%. The digestible calories in beef rises by 15% on cooking, and in sweet potato some 40% (the exact change depends on whether it is boiled, roasted or microwaved). So significant is this impact that Richard Wrangham, a primatologist at Harvard University, reckons that cooking was necessary for human evolution. It enabled the neurological expansion that created Homo sapiens: powering the brain consumes about a fifth of a person’s metabolic energy each day (cooking also means we didn’t need to spend all day chewing, unlike chimps).
The difficulty in counting accurately doesn’t stop there. The calorie load of carbohydrate-heavy items such as rice, pasta, bread and potatoes can be slashed simply by cooking, chilling and reheating them. As starch molecules cool they form new structures that are harder to digest. You absorb fewer calories eating toast that has been left to go cold, or leftover spaghetti, than if they were freshly made. Scientists in Sri Lanka discovered in 2015 that they could more than halve the calories potentially absorbed from rice by adding coconut oil during cooking and then cooling the rice. This made the starch less digestible so the body may take on fewer calories (they have yet to test on human beings the precise effects of rice cooked in this way). That’s a bad thing if you’re malnourished, but a boon if you’re trying to lose weight.
One problem was that his sums were based on the idea that calorie counts are accurate. Food producers give impressively specific readings: a slice of Camacho’s favourite Domino’s double pepperoni pizza is supposedly 248 calories (not 247 nor 249). Yet the number of calories listed on food packets and menus are routinely wrong.
Susan Roberts, a nutritionist at Tufts University in Boston, has found that labels on American packaged foods miss their true calorie counts by an average of 8%. American government regulations allow such labels to understate calories by up to 20% (to ensure that consumers are not short-changed in terms of how much nutrition they receive). The information on some processed frozen foods misstates their calorific content by as much as 70%.
That isn’t the only problem. Calorie counts are based on how much heat a foodstuff gives off when it burns in an oven. But the human body is far more complex than an oven. When food is burned in a laboratory it surrenders its calories within seconds. By contrast, the real-life journey from dinner plate to toilet bowl takes on average about a day, but can range from eight to 80 hours depending on the person. A calorie of carbohydrate and a calorie of protein both have the same amount of stored energy, so they perform identically in an oven. But put those calories into real bodies and they behave quite differently. And we are still learning new insights: American researchers discovered last year that, for more than a century, we’ve been exaggerating by about 20% the number of calories we absorb from almonds.The process of storing fat – the “weight” many people seek to lose – is influenced by dozens of other factors. Apart from calories, our genes, the trillions of bacteria that live in our gut, food preparation and sleep affect how we process food. Academic discussions of food and nutrition are littered with references to huge bodies of research that still need to be conducted. “No other field of science or medicine sees such a lack of rigorous studies,” says Tim Spector, a professor of genetic epidemiology at Kings College in London. “We can create synthetic DNA and clone animals but we still know incredibly little about the stuff that keeps us alive.” (...)
Our fixation with counting calories assumes both that all calories are equal and that all bodies respond to calories in identical ways: Camacho was told that, since he was a man, he needed 2,500 calories a day to maintain his weight. Yet a growing body of research shows that when different people consume the same meal, the impact on each person’s blood sugar and fat formation will vary according to their genes, lifestyles and unique mix of gut bacteria.
Research published this year showed that a certain set of genes is found more often in overweight people than in skinny ones, suggesting that some people have to work harder than others to stay thin (a fact that many of us already felt intuitively to be true). Differences in gut microbiomes can alter how people process food. A study of 800 Israelis in 2015 found that the rise in their blood-sugar levels varied by a factor of four in response to identical food.
Some people’s intestines are 50% longer than others: those with shorter ones absorb fewer calories, which means that they excrete more of the energy in food, putting on less weight.
The response of your own body may also change depending on when you eat. Lose weight and your body will try to regain it, slowing down your metabolism and even reducing the energy you spend on fidgeting and twitching your muscles. Even your eating and sleeping schedules can be important. Going without a full night’s sleep may spur your body to create more fatty tissue, which casts a grim light on Camacho’s years of early-morning exertion. You may put on more weight eating small amounts over 12-15 hours than eating the same food in three distinct meals over a shorter period.
There’s a further weakness in the calorie-counting system: the amount of energy we absorb from food depends on how we prepare it. Chopping and grinding food essentially does part of the work of digestion, making more calories available to your body by ripping apart cell walls before you eat it. That effect is magnified when you add heat: cooking increases the proportion of food digested in the stomach and small intestine, from 50% to 95%. The digestible calories in beef rises by 15% on cooking, and in sweet potato some 40% (the exact change depends on whether it is boiled, roasted or microwaved). So significant is this impact that Richard Wrangham, a primatologist at Harvard University, reckons that cooking was necessary for human evolution. It enabled the neurological expansion that created Homo sapiens: powering the brain consumes about a fifth of a person’s metabolic energy each day (cooking also means we didn’t need to spend all day chewing, unlike chimps).
The difficulty in counting accurately doesn’t stop there. The calorie load of carbohydrate-heavy items such as rice, pasta, bread and potatoes can be slashed simply by cooking, chilling and reheating them. As starch molecules cool they form new structures that are harder to digest. You absorb fewer calories eating toast that has been left to go cold, or leftover spaghetti, than if they were freshly made. Scientists in Sri Lanka discovered in 2015 that they could more than halve the calories potentially absorbed from rice by adding coconut oil during cooking and then cooling the rice. This made the starch less digestible so the body may take on fewer calories (they have yet to test on human beings the precise effects of rice cooked in this way). That’s a bad thing if you’re malnourished, but a boon if you’re trying to lose weight.
by Peter Wilson, 1843 | Read more:
Image: Paul Zak
