by guest blogger George Grunfelder, 4th year nutrition student, Winthrop University
Quick, think of a diet, any diet at all. Got one? Alright.
Is it the keto diet? I would be surprised if it wasn’t!!
The keto diet is everywhere nowadays! Instagram, Facebook, your best friend, even your uncle, you name it and they are raving about the amazing results they have achieved. Stories of rapid weight loss, improved brain function, and decreased sugar cravings flood social media, but is keto truly healthy? Let’s break it down.
How does the keto diet work? This is a low-carb, high-fat diet that forces our bodies to burn fat as its main source of fuel. By default, our bodies naturally rely on carbohydrates as our main source of fuel. Carbs are broken down into glucose, which is used in every process of metabolism. The keto diet uses an extreme carbohydrate restriction and fat surplus approach to eating in order to put the body in a state of ketosis. During ketosis, the liver turns fat into something called ketones, which can supply energy. The concept is pretty simple: by using fat as the main source of energy, you can eat more of the guilty pleasures you enjoy, burn stubborn body fat, and lose weight. But is it really that simple?
Not exactly. The human body has evolved to very efficiently use glucose as its primary fuel source. It is the reason we crave carbs. Being in a state of ketosis is a lot like being in a starvation state. We are starving the body of the easy-to-use carbohydrates it functions best on. Ketosis requires strict adherence to a 5% carbohydrate diet, because it only takes as little as 100g of carbs per day to break ketosis. Entering ketosis has been described as going through a flu-like period of increased irritability, brain fog, hunger, and low energy. Common signs you have entered ketosis and have begun to burn ketones as your primary energy source include purple urine, rotten apple breath, and a positive ketone urine test. So what draws so much support for this diet?
Rapid weight loss is often cited as one of the main reasons people are attracted to the keto diet. It is true, studies have shown that based on weight alone, keto seems like a viable option for weight loss. It is critical to realize what is actually happening under the surface, as the scale can be misleading. When compared to a low-fat diet that resulted in 3 pounds of weight loss, the low-carb diet resulted in 4 pounds of weight loss. Unfortunately, analysis revealed that the keto diet weight-loss was a result of shedding water weight as well as a higher percentage of lean muscle mass!1 The reasoning behind this is that carbs are either used as glucose for blood sugar control or stored in the muscles as energy in the form of glycogen. Each gram of glycogen requires ~2g of water to utilize. Water weight is also lost through the kidneys as they must use water to filter out ketones. This water weight-loss slows down after 1-2 weeks.2 Furthermore, research has shown that while weight-loss was higher on a keto diet, fat loss was actually halved when compared to a low-fat diet.3 The last thing I’d like to point out in regards to weight-loss on a keto diet is that by cutting out carbohydrates, it is very likely that you’d be cutting out many calorie-rich, processed foods. This would result in a calorie deficit, which causes weight-loss.
Now that we know the keto diet doesn’t lead to sustainable weight-loss or a reduction in body fat percentage, it might be useful to highlight some of the risks associated with this style of eating. One major issue with eliminating nearly all carbs from your diet is developing nutrient deficiencies. Carbohydrate foods include many of the most nutrient dense foods on the planet, such as most vegetables, fruits, grains, and legumes. These are rich in vitamins, minerals, fiber, phytonutrients, and antioxidants. Low-carb diets such as the keto diet have been shown to increase risk of all-cause mortality.4 Proponents may point to the touted weight-loss and claim that this leads to decreases in cholesterol levels, but this has been disputed. While weight-loss in general correlates with decreased cholesterol, individuals on a keto or Atkins diet (low-carb) blunted or even neutralized this effect.5 Many of those promoting a keto diet claim that it is a healthy way to treat and even reverse type 2 diabetes. I guess it depends on your definition of reverse. By avoiding carbs, people with diabetes can see a drop in blood sugar levels, but this is moreso treating the symptoms than the underlying disease. The symptom is uncontrolled glucose. The disease is carbohydrate intolerance. In order to truly make the claim that a diet has reversed type 2 diabetes, the person would need to be able to eat carbs without issue, rather than completely avoid them.
Now it might seem like I am strictly anti-keto with a passion, but that isn’t true. I have family members who claim it helps with symptoms of narcolepsy, and for that I say hurray. Research does support keto as an effective treatment for epilepsy in children as well. Many people stick through it and feel that it works for them, and in the end, it is a personal choice. My goal was to share some of the lesser talked about points of this popular diet that are worth thinking about. Hopefully you gained a deeper understanding of this trendy diet.
1. https://www.sciencedirect.com/science/article/pii/S1550413115003502?via%3Dihub
2. https://jamanetwork.com/journals/jama/fullarticle/196324
3. https://www.ncbi.nlm.nih.gov/pubmed/28074888