To Keto or Not to Keto: The Truth About Diet Trends.

​As a Registered Dietitian, my clients (and friends, and family…) are frequently asking me for my take on popular diet trends. I’ve said it before and I’ll say it again: everyone is looking for that “magic bullet,” the one change that they can make to improve their health or lose weight. But the simple fact of the matter is its not nearly that simple. There is a reason we RDs go to school for 4+ years to earn our credential: nutrition is complicated.
 
That said, I feel as though my clients have a right to know fact from fiction. So when asked about popular diet trends my response usually is to present them with the facts (good and bad) and let them decide for themselves. In this post I’ll do just that: break down several popular diet trends that I am asked about frequently and present the facts about each. Let me be clear in that I am not recommending these diets nor am I not recommending them. I am simply providing you with the information that is accurate and unbiased. Always consult your doctor and preferably an RD before making changes to your diet or exercise routine.
 
Before I delve into the nitty gritty, let’s take a step back and discuss the broader topic: diets. The word “diet” can mean a lot of things to a lot of people. Technically speaking it refers to what you eat on a day-to-day basis. That means the good, the bad and of course, the ugly.  However the word “diet” in our culture has come to mean something entirely different. When we say we’re “on a diet” or “following an xyz diet” we often are referring to a temporary way of eating to achieve some health or fitness outcome. But once we reach our goal what happens to the diet? Most of us fall off the wagon. Very rarely do people consider diets to be lifelong modifications, largely because they are restrictive in one way or another, and as such are not sustainable.  The three diets presented in this post are no exception. 

---

---

Keto

​One of the most popular diet trends that has gained substantial traction over the last few years is the ketogenic diet (KD). Originally studied as a treatment option for medication-resistant seizure disorders, the KD has evolved into the latest diet trend for weight loss, diabetes management and overall health. As the name suggests, the KD aims to put the body in a state of ketosis. This is accomplished by extreme carbohydrate restriction thus forcing the utilization of fat as a primary fuel source. While there is certainly validity to the use of the KD under certain conditions and medical supervision, the diet is not a one-size-fits-all for overall health.
 
For the last several years the term “keto” has become an increasingly prominent buzzword in both the popular media and healthcare field. For decades the KD has been an effective strategy for managing treatment-resistant seizure disorders, although the exact mechanism for its success is still unclear. More recently the KD has gained notoriety for its success in lowering HgA1c levels and improving glucose control in patients with type 2 diabetes.1,2 Additionally the diet does appear to produce weight loss and improve blood lipids in patients with and without diabetes. However it remains unclear as to whether these results are the result of patients reaching a state of ketosis or a simple calorie deficit.1-3
 
Despite the evidence to support KD’s success, the question remains of its sustainability. The severe carbohydrate deficit promoted by the KD excludes foods like fruits, some vegetables and whole grains that contain vital nutrients essential for cellular function and optimal health. Excluding these food groups for prolonged periods of time puts individuals following the KD at risk for a variety of nutrient deficiencies that could negatively impact immune health, gut function and overall health.  Furthermore, many patients report negative effects such as irritability, headaches, lack of energy, GI distress and sleep disturbances.4 Finally, research has shown that patients who lose weight following the KD quickly gain it back once carbohydrates are added back into the diet.
 
Conclusion: Approach keto caution. Historically the KD has been used as a last resort to treat seizure disorders that were not remediable by other means, and was only done so under strict medical supervision that included a Registered Dietitian specialized in the diet and it’s potential side effects. Although it can be easy to be swayed by all of the hype, including clinical data, surrounding the “keto craze,” keep in mind that a diet that so drastically restricts a fundamental macronutrient, will likewise drastically affect the big picture of your health, not just one component of it.

---

---

Intermittent Fasting

​Another growing trend in the “diet” world is the concept of intermittent fasting (IF). IF regimens vary depending on the needs of the individual, but most involve either days/hours of fasting followed by days/hours of unrestricted intake. For example, patients may follow alternate-day fasting in which they fast for an entire day followed by a day of unrestricted eating. Others may follow a 5:2 fast in which they “fast” 2 days per week by eating only 25% of their usual intake and eating 100% of their usual intake on the remaining 5 days per week. Others still will restrict food consumption to certain hours of the day (typically midday) and fast the remaining hours outside of that timeframe.  Regardless of the specific regimen followed, all intermittent fasting works in the same way: a calorie deficit is created by periods of restricting food intake.
 
Now, let’s get into the science. Many popular news articles will promote the idea that biologically, the human metabolism evolved to operate under intermittent fasting conditions. This is based on historical data from the days of hunting and gathering when our ancestors did indeed experience periods of fasting and famine followed by periods of abundant food supply. While the historical context of this assumption is likely correct, the impact it has had on the human metabolism is merely a speculation. To date, there is no scientific evidence to suggest that intermittent fasting in any way improves nutrient metabolism or health outcomes. In fact, several studies have found the opposite. In clinical trials IF showed no significant improvement in weight loss outcomes, insulin sensitivity, blood glucose control or blood lipids when compared to standard calorie restriction (25% reduction in calorie intake) on a daily basis.5-7 Furthermore, patients in the IF group reported more adverse effects such as irritability, hunger and low-energy level, and had significantly higher drop out rates than their comparison groups.6,7
 
Conclusion: Science suggests that IF is approximately as effective as any other form of calorie restriction in producing weight loss, insulin sensitivity and other health outcomes. That said, there does not appear to be any advantage of intermittent fasting over any other form of calorie restriction. However there do appear to be more drawbacks. While IF may work well for some, patients in clinical trials reported feeling worse, and maintained the diet for less time than other diets. Furthermore, IF provides no guidance as to the types of foods consumed during non-fasting periods. While I’m sure some individuals who follow intermittent fasting regimens do eat well-balanced diets, I am always hesitant to endorse a diet does not provide instruction as to how to maintain a balanced diet within the parameters of the diet. 

---

Paleo 

​Last, but certainly not least: the Paleo diet. This diet restricts food consumption to foods that were eating during the Paleolithic Age, i.e. the stone-age. The argument here is similar to that of intermittent fasting: the human body has evolved to eat certain types of foods that were available to our ancestors. Similarly Paleo advocates claim that the refined, processed foods that comprise the majority of our modern, “western” diet are not optimal for human health. Foods included on the Paleo diet are whole, raw foods such as raw fruits and vegetables, nuts and seeds, lean meats and fish. Foods excluded include grains, legumes, dairy products, refined sugars and processed foods.
 
So let’s break it down point by point. As an RD, I’m all for a diet rich in fruits and vegetables. Personally, I don’t feel as though they need to be raw to be healthy. However I will agree that the less processing of any food (including cooking), the more it retains it’s natural nutritional value. That said, Paleo’s avoidance of grains and legumes concerns me as both food groups are a great source of fiber, vitamins and minerals. Additionally, a hallmark of the Paleo diet is an avoidance of any processed food. Here I think there is a good point. Many of the foods we eat today wouldn’t even be recognized as food just a few generations ago. Industrialization of agriculture and the food industry has drastically changed the way we eat, and as a consequence, the way we think about food.
 
Conclusion: Parts of the Paleo diet are nutritionally sound: specifically, the focus on fruit and vegetable consumption and avoidance of processed foods. That said, avoiding foods such as grains and legumes could lead to deficiencies if consumers do not possess the nutrition knowledge necessary to consume a balanced diet. 

---

---

So what should ​ you do?

So there you have it: my take on three of the biggest diet trends of the 21st century. When it comes to diet I personally believe in the mantra “Everything in moderation, including moderation.” In my professional opinion, it is unrealistic, and in many ways unsafe, to practice severely restrictive eating for long periods of time. So I always encourage my clients to make small changes that they can maintain, and over time they will make big differences. I gladly welcome comments, questions and of course, appointments! 

---

References:

1. Azar, S., Beydoun, H., and Albardri, M. (2016). Benefits of ketogenic diet ofr management of type two diabeites: A review. Obesity and Eating Disorders, 2(22). 
2. Hussain, T., et al. (2012). Effect of low-calorie versus low-carbohydrate ketogenic diet in type 2 diabeites. Nutrition, 28. 1016-1021.
3. Feinman, R., et al. (2015). Dietary carbohydrate restriction as the first approach in diabetes management: Critical review and evidence base. Nutrition, 31. 1-13.
4. Paola, T. et al. (2017). Distinct circadian signatures in liver and gut clocks revealed by ketogeneic diet. Cell Metabolism, 26, 523-538.
5. Mattson, M.P., et al. (2017). Impact of intermittent fasting on health and disease processes. Aging Research Reviews, 39, 46-58.
6. Horne, B.D., Muhlestein, J. B. and Anderson, J. L. (2015).  Health effects of intermittent fasting: hormesis or harm? A systematic review. American Journal of Clinical Nutrition, 102 (2).
7. Harris, L. et al. (2018) Intermittent fasting interventions for the treatment of overweight and obesity in adults aged 18 and over: a systematic review and meta analysis. Accepted manuscript: JBI Database of  Systematic Reivews. ​