There are three words, one sentence, one statement, that if I had a dime for every time I heard it, I’d probably be writing this blog from a private beach in the Bahamas! I hear it from everyone: bodybuilders, athletes, soccer moms, you name it. I even hear it on the news and read it in articles…I can’t escape it! “I’m cutting carbs.” Our society has managed to turn “cutting carbs” into a money-making machine by taking advantage of consumers looking for another “quick fix.” Somehow people have forgotten that our bodies NEED carbohydrates. I can’t say I blame anyone for getting lost in the thicket of fad diets, bad advice, and infomercials, but it’s time to get back on track and discover the real truth about carbohydrates. Why do our bodies need carbohydrates? What happens when we are carb-depleted? Why have so many people had “success” with these “low-carb” diets? Let’s take a look.
First let’s talk about why carbohydrates (CHO) are important. There are four macronutrients that everyone must consume to survive. They are carbohydrate, fat, protein and water. So, when someone tells me they are going to cut carbohydrates from their diet, it just doesn’t make sense. They would never consider cutting water from their diet, so why would cutting CHO be a good idea? It’s not! In fact, carbohydrates are the macronutrient our bodies require in the largest amounts. According to the Dietary Reference Intakes published by the USDA, 45% – 65% of daily calories should come from carbohydrates. Carbohydrates are the body’s main source of fuel. As a meal containing carbohydrates is eaten and digested, blood glucose levels rise. All of the tissues and cells in our body can use glucose for energy. Carbohydrates are needed for the central nervous system, the kidneys, the brain, and the muscles (including the heart) to function properly. Carbohydrates can be stored in the muscles and liver (as glycogen) to be used later as energy and are also important in intestinal health and waste elimination. These are the facts. These are not ideas or suggestions; this is what we KNOW about carbohydrates.
I know, I know, I’ve already heard what you are thinking: “But I’ve had success losing weight in the past on a low carbohydrate diet.” And, I don’t doubt that you have lost weight, maybe up to 5lbs in the first week! What you need to understand is “weight loss” is not “fat loss.” Fat loss comes from a caloric deficit. If you eat fewer calories than you burn, you will lose fat mass. It has very little to do with the type of calorie you are eating (carbohydrate, protein, fat). It has everything to do with the AMOUNT of calories you are consuming.
There is a very good explanation for the rapid weight loss associated with a low carbohydrate diet. Because the body’s demand for sugar is constant, body glycogen stores are depleted in the early phases of a low carbohydrate diet. Glycogen (stored CHO) is hydrated with 2-4 grams of water/gram of glycogen (fat only contains 0.5 grams of water/gram). Therefore, each gram of stored CHO lost includes two to four grams of water. This loss in water is reflected on the scale as “weight loss” not “fat loss.” In the following weeks, water equilibrium is re-established, so the remaining weight loss simply reflects the calorie deficit associated with cutting carbs – it has nothing to do with the carbohydrate itself.
Some advocates of the low CHO diet maintain that restricting dietary carbohydrates causes the body to enter a state of ketosis. Simply put, ketosis is when the body breaks down stored fat as energy. In a CHO-restricted state, our bodies generate excess ketones that are byproducts of INCOMPLETE fat breakdown. These ketones are lost in the urine and, at best, only represent about 100-150 kcal per day. This would equal about 1lb of weight loss per month, which is not significant considering you should be able to lose 1-2lbs/week.
Compared to a well-balanced diet, CHO restriction shows no advantage in facilitating fat loss. The diet even poses potential health hazards, including:
• Altered electrolyte balance, increasing the risk of cardiac arrhythmias
• Impaired kidney function
• Significant increase in cholesterol levels
• Reduced blood sugar and stored CHO levels, resulting in extreme fatigue, confusion, impaired cognitive function, depression and irritability
• Dehydration
• Breakdown of substantial amounts of muscle tissue as a fuel source, resulting in reduced metabolism and functional capacity impairments
• Greatly impaired exercise performance caused by low blood sugar, making it difficult to see any significant fitness adaptation from exercise.
Do any of these health hazards sound desirable (or even smart) to anyone reading? Yeah, I didn’t think so! This is particularly true when you consider that NO ONE can maintain a low carbohydrate diet forever, because the body simply won’t allow it. Eventually, your body’s “drive to survive” will result in the consumption of carbohydrates once again. So, even if these health hazards didn’t exist, and even if cutting carbs worked (which it doesn’t), weight loss wouldn’t last because it is not sustainable.
Simply put, if you are cutting one of your macronutrients, you are cutting calories. If you cut 500 calories of carbohydrate per day, you will lose 1lb of fat/week. If you cut 500 calories of fat per day, you will also lose 1lb of fat/week. Water lost by reducing CHO does not reduce body fat! The secret to a successful weight loss program is simple…..eat less, move more….there I said it!