We have known for years that we are covered in microbes and they matter a lot , but only recently has the study of these microbes become cool, thanks in part to new tools. Lynn Margulis was arguing in the late s that organisms were nearly all engaged in symbioses that defined who they were.
Margulis studied the symbionts of protists and termites what we now call their microbiomes. She could look at the symbionts of the protists when they were still alive and she could cut open the termites Which she did hundreds of times; it was one of her greatest joys.
With humans, studies of symbionts usually involve fecal samples, which is a bit like studying the center of the Earth by looking at lava, if, I guess, the lava were feces. Something of the grandeur is missed. The recent literature on human symbionts is wondrous but still groping at the edge of understanding. Scientists study the microbes in the feces from twelve white dudes from New Jersey and make an announcement about the entirety of humanity.
One would be reasonable to be suspicious of anyone claiming to have understood the simple truths of the microbes in our guts. Nonetheless, differences among individual humans in their symbionts do seem to make differences in how they digest food—individuals appear to differ in their metabolism depending on just which microbes they have.
In addition, some microbes are found only in particular peoples where they appear to play a unique role. In some Japanese populations lives a gut microbe that has stolen genes from a marine bacterium ; those genes help the bacterium to break down seaweed such as that encountered in sushi rolls. How you digest food depends on which microbes you have and which microbes you have differs from one person to the next.
Different foods can both affect and be affected by our microbes. Hunter-gatherer diets in the southwestern U. Conversely, many modern diets provide very little good food for microbes, very likely to our detriment. Microbes seem likely to suffer on a diet of cheese product and white bread because both are used up by the time they make it to the colon. Margulis would have predicted all of this forty years ago based on termites We seem to more easily accept mice as models of our bodies than we do termites.
A Calorie is Not a Calorie —When all is said and done the good news is we have figured how to make and eat foods in which the calories are maximally available. We process them. We cook them. We ferment them. We cook them again until they actually give us as many calories as the box says. Our ancestors may have combined a preference for cooked food with the unique ability to make it on demand. But for as much as they like grilled steak, they will never invent cooking. We did. If this idea is right, what we inherit as our unique recent history is not the need for some specific amount of meat or fat but instead the preference for as many calories as we can get as quickly as we can get them so that we might have leisure time to invent, organize, and text each other.
It is a testament then to human ingenuity that we have now figured out how to provide as many calories as possible in our foods. Our modern diets are a measure of our evolutionary success, or at least they would be from the perspective of our paleo ancestors who needed and wanted excess calories.
They are not successes from our modern perspective. We now have too many calories and too many of those calories are of low quality. One in three Americans is now obese.
Over the last thirty years the number of calories we eat has increased, but so has the number of those calories that come from highly processed foods. The rest might be used by bacteria in your colon, or might even be passed out whole. Even among cooked foods, digestibility varies. A study at Oxford University found that the fat in your food ends up on your waistline in less than four hours.
Carbohydrate and protein take a little longer, because they need to be converted into fat in the liver first and it takes nine calories of protein or carbohydrate to make 1g of fat. An individual eating an extra calories per day will gain weight faster. The short answer is your calories start the process of turning into fat as soon as 4 hours after eating them.
But it would take a couple of weeks of eating too many calories for that fat to show up in a meaningful way. When people eat calories in the form of solid food, they naturally compensate by reducing the rest of their food intake. Indeed, many people with bulimia actually gain weight over time. Your body starts absorbing calories from the moment you put food in your mouth. According to the Daily Mail, Oxford University research found that dietary fat takes an hour to enter our bloodstream post-meal, then two more hours to get into our adipose tissue i.
While the actual rate people can gain weight varies and depends on the individual and their metabolism, age, height, fitness and state of health, it does not happen overnight. When your calorie intake is too low, you may not get all the nutrients your body needs.
In the long run, this slowing metabolism can lead to weight gain. Enzymes in the stomach further break the food down, before most of the absorption taking place in the small intestine. Weight gain and fluctuations in weight can happen for a variety of reasons. Many people progressively gain weight as they age or make changes to their lifestyle. If you eat the same food cooked, you will tend to gain weight. Same calories, different outcome.
For our ancestors, it could have meant the difference between life and death. Hundreds of thousands of years ago, when early humans learned to cook they were able to access more energy in whatever they ate. The extra energy allowed them to develop big brains, have babies faster and travel more efficiently. Without cooking, we would not be human. Animal experiments show that processing affects calorie gain whether the energy source is carbohydrate , protein or lipid fats and oils. In every case, more processed foods give an eater more energy.
Their energy is often packaged in starch grains, dense packets of glucose that are digested mainly in your small intestine.
If you eat a starchy food raw, up to half the starch grains pass through the small intestine entirely undigested. Your body gets two-thirds or less of the total calories available in the food. The rest might be used by bacteria in your colon, or might even be passed out whole. Even among cooked foods, digestibility varies. Starch becomes more resistant to digestion when it is allowed to cool and sit after being cooked, because it crystallizes into structures that digestive enzymes cannot easily break down.
Our bodies are functioning the same way. They do little to consume food that has been softened by boiling, mashed, or aerated. Our favorite meal has lovingly cooked that it melts in the mouth and slips down our throats with hardly any need for chewing. If we want to lose weight, we need to question our instinctive urges. We can reject soft white bread for the sake of hard whole wheat bread, fine cheese for real cheese, and cooked vegetables for raw vegetables.
And it would be much better if our food labels provided us any guidance about how much calories we would gain from consuming fewer refined foods. So why are our diet advisers mute on the subject?
For decades, distinguished commissions and institutions have called in to change our calorie-counting method. Yet the call for reform has stalled.
The issue is a lack of knowledge. Researchers find it impossible to determine precisely how much additional calories can be obtained as our food is more heavily refined.
On the other side, they find it convenient to prove that if the food is completely digested, it can contain a certain amount of calories. The first provides a specific number of calories. Still, it does not consider the established effects of food production and thus does not quantify what our bodies are currently harvesting from food.
In the face of this tough decision, any nation has decided to disregard the impact of processing, and, as a result, customers remain confused. Labels have a figure that is likely to overestimate the calories found in unprocessed foods.
Prices for refined products are smaller, so the level of overestimation on their labels is larger. Negative-calorie food is food that supposedly takes more food energy to digest than food resources. Despite its recurring prevalence in nutritional manuals, there is no empirical data to endorse that all meals are calorically harmful. Although certain refrigerated drinks are calorically acidic, the result is marginal and needs a significant volume of water to consume, which can be harmful since it may induce water poisoning.
There is no empirical data to suggest that all of these ingredients have a harmful calorific effect. Foods believed to be negative in calories are mainly low-calorie fruit and vegetables such as celery, grapefruit, citrus, lemon, lime, apple, spinach, broccoli, and cabbage.
Diets focused on negative-calorie food do not function as advertised but can contribute to weight loss since they satisfy appetite by loading the stomach with food that is not heat rich. A research focused on a low-fat plant-based diet showed that a typical person had lost 13 pounds 5. Another research found that harmful calorie diets NCDs had the same effect as low-calorie diets LCDs as weight reduction caused by exercise. Looking at this as a digestive system, the mechanism of digestion requires resources to operate.
Chemicals are released, muscles pushed to drive the food into the system.
0コメント