By Jordan Lichthardt, MS, RD, LD

If you are like many Americans, it is likely that you have tried a fad diet or two. As a Registered Dietitian, I face many questions about which diets are safe and which will yield the best results. In this article, I offer detailed insight into three of the most popular diets of today’s age. Read on to find out which diets you need to stay clear of, and which ones may have some surprising health benefits.

Ketogenic diet

How it works:​ The ketogenic diet in essence removes all carbohydrates from the diet, which are your body’s preferred source of energy, and replaces those calories with fat. When this happens, normal cellular processes cannot be completed, which in-turn causes your body to produce a fat-derived product known as a ketone. Ketones then become substitute energy sources for most cells in your body.

Benefits​: The ketogenic diet has been scientifically proven to be beneficial for children with epilepsy. But most people are using the ketogenic diet for weight loss, not epilepsy. If this is you, I can assure you that you will likely lose weight. With the elimination of carbs, you also lose water weight. Just be warned that your weight loss is definitely not all body fat, and you’ll likely gain the weight back when you add carbs back into your diet.

Drawbacks:​ If you have ever tried the ketogenic diet, you may notice that after a few days, you feel groggy, run-down, have a headache, experience sleep problems, or may even have bad breath. This is because the body–particularly the brain–relies on carbohydrates for energy. When you take the body’s energy source away, you too, feel like you have no energy. Additionally, you will be missing out on important vitamins and minerals found in foods with carbohydrates, including fruits, vegetables and grains. Instead, you will be eating more meat, oils, butter, cheese, and nuts. Even though some of these foods are healthy, you will likely increase your intake of saturated fat (think bad cholesterol) and sodium (think high blood pressure).

Final verdict​: This is not a diet that I recommend as a dietician. In addition, think about this: could you really live your life without any bread, pasta or desserts? I know I couldn’t.

Intermittent fasting

How it works​: Fasting is not a new concept. It has been around for hundreds of years. The idea of intermittent fasting, however, has recently made its presence known in the diet world. There are three main ways to follow this diet. One, have a day of complete fasting (zero caloric intake) followed by a day of unrestricted intake. Two, follow the 5:2 structure: five days of normal eating, followed by 2 days of modified fasting (consuming ~500 calories on these days). Finally, follow a time-restricted structure. This is likely the most popular approach, where you have a specified eating window each day (say noon to 6 p.m.), and you fast the remainder of the day. People who follow this method generally skip breakfast, but eat lunch and dinner with snacks in between. Regardless of the type of intermittent fasting, the fundamental idea is that fasting of some sort can help rewire the way your body responds to stress, which in turn has several health benefits.

Benefits​: Because intermittent fasting limits the amount of time you have access to food, it may be easier for some people to achieve a caloric deficit, leading to weight loss. Additionally, you have the flexibility to eat what you want on non-fasting days/times, which can help alleviate the stress of dieting. Proponents of intermittent fasting also claim that it can lower inflammation, reduce the risk of diabetes, increase cognitive function, help you sleep better, and even help you live longer. So what’s the catch? Much of the research examining the health benefits of fasting has been conducted in rodents, not humans. Thus, there is still much to be learned about this approach.

Drawbacks​: Recent studies have shown that compared to those who followed a traditional calorie restriction, those who followed intermittent fasting did not have significantly different weight loss, or significant differences in biomarkers for disease. However, the intermittent fasting group did have a higher dropout rate. Overall, this indicates that intermittent fasting may be more difficult to follow than traditional dieting, but yield similar results. Other negative side effects include dealing with persistent hunger on fasting days; feeling cold, distracted, and irritable; and being more likely to binge on non-fasting days due to the increased release of dopamine when you do eat.

Final verdict​: As a registered dietitian, I am skeptical towards intermittent fasting. Although I think some people may be able to achieve successful weight loss with this method, more research is needed. For now, I am still going to advocate starting your day with a healthy breakfast, and eating regular meals throughout the day to keep your metabolism at its peak.

Mediterranean diet

How it works:​ This diet mimics the food choices and the lifestyle of the people who live in the countries surrounding the Mediterranean Sea. In general, the Mediterranean diet is rich in fruits, vegetables, beans, and whole grains. Just to clarify, whole grains in this diet means more quinoa, couscous, and polenta, and less pasta. There are moderate amounts of nuts, yogurt, cheese, olive oil, fish, and even wine.  
Processed foods, red meats, and sweets are eaten very seldomly. Meals are eaten together with friends and family at a leisurely pace, without any distractions.

Benefits​: The obvious benefit of eating a more plant-based, minimally processed diet is weight loss. However, the Mediterranean diet has been shown to significantly reduce your risk of diabetes. And when I say significant, I mean it. One study showed that those who followed the Mediterranean diet (as compared to a low-fat diet) were over 50% less likely to develop the disease. Because the diet is rich in antioxidants, fiber, and healthy fats, it also helps to decrease the risk of cancer, heart disease, and even dementia. Finally, you may naturally eat less on the Mediterranean diet, since there is an emphasis on slowing down and savoring your food.

Drawbacks​: There are not very many cons to this diet, but there are a few to be aware of. First, this diet can be relatively high in calories. If you are not mindful of portion sizes, it would be very easy to overindulge in calorie-dense foods such as nuts. Second, this diet may not be culturally practical for you. Living in Northern New Mexico, many of us (including myself) enjoy foods such as burritos, enchiladas, and tamales. You may also have limited access to fresh fruits and vegetables or seafood, or have a family member that suffers from food allergies associated with these foods. While it may be one of the healthier diets that are popular today, you need to decide for yourself if the Mediterranean diet is practical for you.

Final verdict​: I would say that the Mediterranean diet is nutritionally well-rounded. It is beneficial for weight loss, but it also offers tons of other health benefits (that have been well-researched!) that other diets do not. If it is feasible, consider trying the Mediterranean diet for yourself.

About Jordan Lichthardt:

Jordan Lichthardt was born and raised here in Los Alamos. After graduating high school, she attended Texas Tech University, where she obtained her Bachelor of Science in Nutritional Sciences. She continued on at TTU and worked diligently to acquire her Registered Dietitian credential, while simultaneously completing her research on the physiological biomarkers of food addiction. She completed her Master’s in Nutritional Sciences in 2017, and then moved back home. Jordan is now enjoying life with her husband and dog Oliver. She is excited to be back in Los Alamos and serve her hometown community as a dietitian.

Lichthardt is now taking consults at Medical Associates of Northern New Mexico- Call 505.661.8900 to schedule an appointment