Eat Raw Food To Lose Weight, Cooked Food Contains More Calories
We’re often encouraged to get into the kitchen and prepare
more home-cooked meals. In fact, nutrition experts suggest that this
strategy could go some way toward a healthier, thinner nation. But, if
the results of a study published last month in the Proceedings of the
National Academy of Sciences is anything to go by, we should be
encouraging people to cook less, or rather, to eat more raw
foods – especially if they have a few extra pounds they need to shift.
The reason? Harvard scientists responsible for the research, found that
cooking food increases the amount of energy or calories that it provides
to your body.
This disparity between cooked and raw fodder is due to the fact that the body uses more energy in digesting raw food than it does cooked food; that more of the energy available from raw food is lost to bacteria in our gut than is the case with cooked food, and that the body expends energy fighting off pathogens that are more prolific in raw food than in cooked.
The unique study which lasted 40 days, relied on 2 groups of mice that were fed a series of diets that consisted of either cooked or raw meat or cooked or raw sweet potatoes. Over the course of the study, the researchers tracked changes in the body mass of the mice, controlling for how much they ate and ran on an exercise wheel.
The results clearly demonstrated that both the cooked protein and cooked starch-rich tuber delivered more energy to the mice than raw variants of both.
“The starting energetic value of a food is based on the composition of that specific food, and that’s not going to change by cooking,” says Rachel Carmbody, the lead researcher on the study. “What cooking alters is the proportion of the energy that our bodies absorbs versus what is lost to gut bacteria, and what is excreted by our bodies. Specifically we believe that cooking reduces the energy that we use up in digestion, while increasing the amount that we absorb.”
“Because cooked food has been processed before it entered the body, some of the work in terms of breaking down that food has already been down so it saves our digestive system from working as hard. Basically cooking externalizes part of the digestive process.”
When it comes to the cooked meat, the heating process gelatinizes the collagen in the muscle and causes the muscle fibers to loosen and separate. This not only makes it easily to chew the meat, but it also increases the surface area exposed to digestive enzymes and gastric acids. As for the cooked sweet potato, here heat gelatinizes the starches and transforms semi crystalline structures into loose, amorphous compounds that are readily broken down or hydrolyzed into sugars and dextrins.
Part of the the gastrointestinal tract also includes a whole host of bacteria, and those bacteria metabolize some of our food for their own energy needs. The small intestine is where most chemical digestion take places. It’s in this 7 meter long tube, that energy for the “human” is absorbed. What remains, passes into the large intestine, and here huge volumes of gut bacteria draw energy from it. “The cooking process allows food to be almost completely metabolized by the time it reaches the end of the small intestine. This means that the body has extracted nearly all of the available energy, leaving little for the bacteria” explains Carmbody. In the case of cooked meat, heating denatures the proteins which unwind from their tightly bound structures and take on a random coil configuration that makes them more susceptible to the enzymes in the small intestine. This ultimately serves to increase the proportion of the protein digested by the body compared to what is digested by gut bacteria in the large intestine.
With raw food, on the other hand, this isn’t the case, and there’s more energy available for the gut bacteria which uses it to carry out a number of functions. For example, energy is used and lost through the production of combustible gases. Also, undigested polysaccharides (fiber) are metabolized by the bacteria through fermentation to produce short-chain fatty acids which are in turn consumed as fuel by the bacteria. “The more energy that’s leftover for the bacteria, the fewer the calories absorbed by the human being,” continues Carmbody.
So what does this all mean, then? Quite simply: If you want to absorb less calories, you should cut down on the cooked portion of your diet, and consume more raw foods. While there is currently no formula to calculate the actual difference in energy absorbed by the body from cooked and raw food, what this study has made clear, is that the existing system of calorie measurement isn’t accurate.
This system, known as the Atwater system, has been used for over 100 years. It measures the calories absorbed by the body by taking the gross calorie measurement of a food and subtracting an estimation of the calories that the body passes out as waste. “It’s basically calories in minus calories out,” explains Carmbody. “But this ignores the differences in how our bodies metabolize cooked and raw foods, and doesn’t account for the energy used in digestion, by gut bacteria, and by the immune system to fight off pathogens.”
Despite the catch-all figure on nutritional labels, you would gain more calories from cooked carrots, spinach or broccoli, for example, than you would if you ate them completely raw as a salad. Of course, if you slather them in Ranch Dressing, well that’s a different story altogether.
This disparity between cooked and raw fodder is due to the fact that the body uses more energy in digesting raw food than it does cooked food; that more of the energy available from raw food is lost to bacteria in our gut than is the case with cooked food, and that the body expends energy fighting off pathogens that are more prolific in raw food than in cooked.
The unique study which lasted 40 days, relied on 2 groups of mice that were fed a series of diets that consisted of either cooked or raw meat or cooked or raw sweet potatoes. Over the course of the study, the researchers tracked changes in the body mass of the mice, controlling for how much they ate and ran on an exercise wheel.
The results clearly demonstrated that both the cooked protein and cooked starch-rich tuber delivered more energy to the mice than raw variants of both.
“The starting energetic value of a food is based on the composition of that specific food, and that’s not going to change by cooking,” says Rachel Carmbody, the lead researcher on the study. “What cooking alters is the proportion of the energy that our bodies absorbs versus what is lost to gut bacteria, and what is excreted by our bodies. Specifically we believe that cooking reduces the energy that we use up in digestion, while increasing the amount that we absorb.”
“Because cooked food has been processed before it entered the body, some of the work in terms of breaking down that food has already been down so it saves our digestive system from working as hard. Basically cooking externalizes part of the digestive process.”
When it comes to the cooked meat, the heating process gelatinizes the collagen in the muscle and causes the muscle fibers to loosen and separate. This not only makes it easily to chew the meat, but it also increases the surface area exposed to digestive enzymes and gastric acids. As for the cooked sweet potato, here heat gelatinizes the starches and transforms semi crystalline structures into loose, amorphous compounds that are readily broken down or hydrolyzed into sugars and dextrins.
Part of the the gastrointestinal tract also includes a whole host of bacteria, and those bacteria metabolize some of our food for their own energy needs. The small intestine is where most chemical digestion take places. It’s in this 7 meter long tube, that energy for the “human” is absorbed. What remains, passes into the large intestine, and here huge volumes of gut bacteria draw energy from it. “The cooking process allows food to be almost completely metabolized by the time it reaches the end of the small intestine. This means that the body has extracted nearly all of the available energy, leaving little for the bacteria” explains Carmbody. In the case of cooked meat, heating denatures the proteins which unwind from their tightly bound structures and take on a random coil configuration that makes them more susceptible to the enzymes in the small intestine. This ultimately serves to increase the proportion of the protein digested by the body compared to what is digested by gut bacteria in the large intestine.
With raw food, on the other hand, this isn’t the case, and there’s more energy available for the gut bacteria which uses it to carry out a number of functions. For example, energy is used and lost through the production of combustible gases. Also, undigested polysaccharides (fiber) are metabolized by the bacteria through fermentation to produce short-chain fatty acids which are in turn consumed as fuel by the bacteria. “The more energy that’s leftover for the bacteria, the fewer the calories absorbed by the human being,” continues Carmbody.
So what does this all mean, then? Quite simply: If you want to absorb less calories, you should cut down on the cooked portion of your diet, and consume more raw foods. While there is currently no formula to calculate the actual difference in energy absorbed by the body from cooked and raw food, what this study has made clear, is that the existing system of calorie measurement isn’t accurate.
This system, known as the Atwater system, has been used for over 100 years. It measures the calories absorbed by the body by taking the gross calorie measurement of a food and subtracting an estimation of the calories that the body passes out as waste. “It’s basically calories in minus calories out,” explains Carmbody. “But this ignores the differences in how our bodies metabolize cooked and raw foods, and doesn’t account for the energy used in digestion, by gut bacteria, and by the immune system to fight off pathogens.”
Despite the catch-all figure on nutritional labels, you would gain more calories from cooked carrots, spinach or broccoli, for example, than you would if you ate them completely raw as a salad. Of course, if you slather them in Ranch Dressing, well that’s a different story altogether.
This article is available online at:
http://www.forbes.com/sites/nadiaarumugam/2011/12/28/eat-raw-food-to-lose-weight-cooked-food-contains-more-calories/
