Calorie Restriction Diets Don't Work Long-Term: How To Boost Metabolism While Eating Carbs
Pasta, bread, cookies, and candy are just a few of the demonized carbohydrates in the modern-day diet. So, Australian researchers set out to prove carbohydrates don’t have to be the enemy for those looking to lose weight or maintain a healthy balance. Their study, published in the journal Cell Reports, is the first to demonstrate how a mouse’s metabolism on a high-carb diet compares to a calorie cutter.
"We've shown that when compared head-to-head, mice got the same benefits from a low protein, high carbohydrate diet as a 40 percent caloric restriction diet," the study’s co-author Stephen Simpson, academic director of the University of Sydney's Charles Perkins Centre, said in a press release. "Except for the fanatical few, no one can maintain a 40 percent caloric reduction in the long term, and doing so can risk loss of bone mass, libido, and fertility."
Simpson and the research team split their mice into three different diet groups and fed each a different mix of carbs and protein for eight weeks. One group was given a low protein and high carb diet (LPHC) with no calorie restrictions, another group was fed LPHC with calorie restrictions, and a third group fed a medium protein-to-carb ratio with calorie restrictions.
It turns out, the group fed LPHC diets without calorie restrictions had a higher metabolism than the mice that were cut off from eating more food. Mice who ate as many carbs as they wanted also didn’t gain more weight or miss out on any of the additional health benefits the restrictive diets provided. Not all carbs were created equal, and this study is one of the first to reveal how healthy carbs can be incorporated into your diet in a beneficial way without depriving yourself.
"It still holds true that reducing food intake and body weight improves metabolic health and reduces the risk of diseases like type 2 diabetes, obesity, and fatty liver disease," Simpson said. "However, according to these mouse data and emerging human research, it appears that including modest intakes of high-quality protein and plenty of healthy carbohydrates in the diet will be beneficial for health as we age."
American diets have a history of hating carbs, from Atkins low-carb diets, which restrict you to an average of 20 grams a day. Meanwhile, the Dietary Guidelines for Americans recommends that carbs should take up 45 to 65 percent of your daily total calories. That means an adult 19 years and older on a 2,000-calorie-a-day diet should eat between 225 and 325 grams of carbs each day — more than 10 times that of the leading low-carb diet’s recommendation. Cutting carbs down and limiting caloric intake is not a sustainable diet or way to lose weight, according to the findings.
Carbohydrates are the body’s main source of fuel, which are broken down into glucose and circulate through the blood with energy. Extra glucose is stored in your liver, muscles, and other cells for later use or eventually stored as fat. They’re an essential part of the diet and help control weight when balanced with fruits and vegetables. But choose your carbs wisely — stick with foods high in fiber, vitamins, and minerals. Limit middling carbs containing added sugars, refined grains, and processed foods that are low in nutrition but high in calories. Whole grains and slow-release carbs, such as oatmeal and brown rice, for example, speed up the metabolism by stabilizing insulin levels. If you choose the right ones, researchers predict you’ll consistently boost your metabolism without gaining unnecessary weight.
The study’s lead author and researcher at the Charles Perkins Centre, Samantha Solon-Biet, looks toward the next steps they have in store for more animal testing and eventually human trials: "An important next step will be to determine exactly how specific amino acids, the building blocks of proteins, contribute to overall health span and lifespan."
Source: Solon-Biet S, Simpson SJ, Mitchell SJ, and Le Couteur DG, et al. Dietary protein to carbohydrate ratio and caloric restriction comparing metabolic outcomes in mice. Cell Reports. 2015.