A new study has re-opened and old question: if you want to lose weight, should you go on a low-fat diet or on a low-carb diet? The study concluded that the low-fat diet is the better choice.
Nutritionists and dieticians have been trying to decide which helps people more for a really long time. Yesterday’s science said that people lose more weight when they go on a low-fat diet, but today’s science says that people lose more weight when they go on a low-carb diet, and tomorrow’s science will says that people lose more weight when they go on a low-fat diet. It’s an endless debate.
As for the new study, it provided proof that low-fat diets should be the ones people run towards. It was conducted by a group of researchers working at the National Institutes of Health (NIH), who took a somewhat unusual approach that while effective, may be hard to apply to the real world.
Kevin Hall, PhD and metabolism researcher over at the National Institute of Diabetes, Digestive and Kidney Diseases, offered a statement revealing what the goal of the study was – he and his team wanted to see if the low-carb theory holds true.
The theory claims that low-carb diets should be favored because they decrease the levels of insulin, a hormone which has the job of regulating fat tissue. Lowering insulin levels is believed to give you a fat-burning edge, however PhD Hall was not convinced, so he set out to investigate how an obese body adapts to receiving fewer carbs how it adapts to receiving less fat.
The researches picked out 19 obese adults, checked them into NIH’s clinical center, and put them through several stages of an experiment. All of the subjects had about the same weight and body mass index (BDI), and the researchers were able to accurately compare how much weight each of them lost by prescribing and monitor every second of exercise and ounce of food.
PhD Hall stressed the importance of this controlled approach by saying that unless researchers “do the kind of study that we have done here, where we basically lock people up for an extended period of time, control everything, and make sure we know exactly what they eat…then we don’t have the kind of control that’s required to answer these really basic questions”.
The subjects were kept at NIH’s clinical center for two (2) weeks at a time. For the first phase of the experiment, the researchers put them on an average diet of 2.740 calories per day – 15 percent (15%) protein, 35 percent (35%) fat, 50 percent (50%) carbs. This phase lasted for five (5) days.
For the second phase, the researchers put subjects on either a low-fat diet, or a low-carb diet. Both of these diets have roughly 30 percent (30%) fewer calories than the first diet. The researchers also had subjects exercise on a treadmill for an hour each day and this phase lasted for six (6) days.
For the third and final stage of the experiment, the researchers put subjects in metabolic chambers for five (5) days. Metabolic chambers are climate-controlled rooms that have been sealed off from the rest of the building. They are connected to various devices that record and analyze the changes that a person goes through.
After looking at all of the data (including hormone levels and metabolite levels), PhD Hall and his team saw that the subjects who had been put on a low-fat diet lost more weight. They managed to get rid of an average of 463 grams, whereas the subjects who had been put on a low-carb diet only managed to lose an average of 245 grams.
But PhD Hall also felt it was important to remind everyone that the experiment relied on strictly controlling a subject’s food intake. He admitted that this approach may not be a very feasible one when it comes to “free-living individuals”.
The study was published earlier this month, in the medical journal Cell Metabolism.
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