Everywhere you turn, people are extolling the virtues of the low carb diet plan. Want to lose weight? “Go low carb.” Want more energy? “Have you tried eliminating carbs from your diet?” Want to better manage your autoimmune condition? “Carbs are the problem!” But skeptics inherently understand what the medical community is now beginning to discover – eliminating an entire food group that sustained our ancestors for millennia may not be the key to long-term health and sustainable weight loss.
“Carbs” are dietary sugars, known as carbohydrates, found in a variety of foods from grain and bread to fruit and vegetables. Several basic metabolic functions go to work when you eat something that has carbohydrate in it. Your blood sugar begins to rise, signaling the pancreas to release insulin to counteract the rising sugar level. Insulin is what allows your cells to absorb carbohydrates and use it for energy.
Once your blood sugar level stabilizes, insulin production slows and energy absorption continues. Carbohydrates are the easiest macronutrient to turn into energy, making it ideal fuel for the brain and muscles. That is why the US dietary guidelines recommend men and women over the age of 50 eat 130 grams of carbohydrates each day, around 45 percent of their daily nutrient intake.
Carbs can be divided into two categories – simple and complex. Simple carbohydrates, also known as sugar carbs, are highly-processed, sugary sources of carbohydrates. When you eat them, your body creates a rapid burst of insulin to counterbalance the increase in blood glucose. However, you tend to metabolize simple carbohydrates quickly, leaving insulin in the bloodstream without a place to go. This “sugar crash” leaves you feeling tired, irritable and often more hungry than you were before.
Fruits, vegetables and whole grains are complex carbohydrates which contain dietary fiber that slows down how fast the body absorbs their sugars. Rather than having a rapid spike in insulin followed by a rapid decline, fiber keeps the blood sugar steady as the body absorbs the nutrients found in food.
Your body is an amazing machine, capable of making adaptations without your knowledge. If you deprive your body of something, it will find a way to adjust its needs so it can still function as long as possible. At one point, scientists believed that there was a minimum amount of carbohydrates a person needed to stay alive. Recent studies have found that the body is capable of maintaining its functions without any carbs in a person’s diet as long as they are consuming enough protein and healthy fats to compensate for a lack of carbohydrate. This is made possible by a process called ketogenesis.
In the absence of carbohydrates, your brain needs a fuel source to keep functioning. While the muscles can burn fat for fuel, the brain requires glucose to work. When you cut carbohydrates from your diet, the liver begins processing fatty acids and producing ketones, a glucose substitute that the brain uses for fuel. Once a person reaches ketosis, they experience rapid weight loss as the body uses fat stores to produce energy for the brain and body. Ketogenesis is enough to keep the body going and can account for up to 70 percent of the brain’s needs, but there are still areas of the brain that require glucose to function.
Enter gluconeogenesis, a process where the liver breaks down amino acids found in proteins and produces its own glucose. Even when your carb intake is very low, your brain will still have its needs met thanks to the work of the liver in these two processes.
There is a term for how you feel in the first several days of starting a low carb diet plan – “carb flu“. Many people who suddenly and drastically reduce the number of carbs they are eating experience headache, weakness, muscle aches, and fatigue as the body adjusts to a new nutritional routine. Some find they are moody, depressed, angry, or anxious in the first days of a low carb diet. Still others experience constipation or diarrhea as their metabolism processes fat or they experience a sudden drop in the amount of dietary fiber they are eating.
As you enter ketosis, you are also more likely to develop bad breath. One of the byproducts of producing ketones is acetone which gives your breath a fruity aroma (and not in a good way). While proponents of the diet claim that increasing the amount of water you drink and eating more healthy fats can combat many of these symptoms, persistent carb flu causes many people to quit a low carb diet before they see results.
There is no arguing with the weight loss results so many people are experiencing on carb-restricted diets. Without carbohydrates for energy, the body attacks fat stores and people drop significant amounts of weight while eating bacon, eggs, avocados, and other fatty foods and proteins. However, by eliminating an entire food group and restricting the intake of things like fruit and certain vegetables, you are also eliminating vital nutrients found in these foods. Important fiber, inflammation fighting antioxidants, metabolism supporting vitamins, and immune-boosting nutrients are found in abundance in fruit and vegetables, but so are carbohydrates.
In the largest longitudinal nutrition study in the world, The China Study found that eating a diet rich in plants can ward off cancer, reverse heart disease, prevent type II diabetes, and improve autoimmune diseases. For people whose goal is to remain in ketosis, the temptation is to eliminate all but the most low-carb elements, relying on leafy greens and certain berries for these nutrients. Still, it is difficult to get the full spectrum of nutrition and the associated health benefits without also consuming plant-based carbohydrates.
Many people on a low carb diet plan love to extoll the virtues of eating bacon and eggs every morning and still losing weight. However, in one of the largest studies of the long-term effects of a low carb diet, researchers found that people who consumed protein and fat from animal sources rather than plant-derived protein and fat sources had a higher 25-year mortality rate. In other words, where people got their protein and fat affected how long they lived. Those who ate vegetables, nuts, peanut butter, and avocados had lower mortality than people who ate bacon, eggs, steak, and chicken in large quantities.
This study is interesting in particular because people with a minimal risk for early death got 50 to 55 percent of their nutrients from carbohydrates. Since not all carbohydrates are created equal, the healthiest study participants consumed plant-based carbohydrates found in fruit and vegetables.
One of the biggest hurdles to a low carb diet plan is sustainability. Rapid weight loss may be the byproduct of burning rat instead of carbohydrates, but as soon as you reintroduce carbs to your diet, you can expect to gain the weight back. This usually happens for two reasons. First, carbs are stored with water in the body. Once you eat a carb-heavy meal, your body not only switches out of ketosis, it retains water. You will notice a change in weight until ketosis is restored. Second, people who reintroduce carbs into their diet often do not eliminate enough fat. Remember, your body can burn fat for energy or carbs for energy, but not both. Carbohydrates are easier to absorb so fat will remain stored until the carb supply is exhausted.
In the end, low carb diets may work in the short-term but do not provide sustainable, healthy weight loss for life. Only balanced diets rich in vegetables and fruits, that include whole grains and lean proteins can create both optimal health and healthy, life-long weight loss.
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