A TALE OF 2 STUDIES: IS KETO REALLY THE ‘BEST’ DIET?

Is there any truth to mainstream diet trends which claim to be ‘the best’? Let’s examine the interpretation of research from different angles for the keto diet.


BY: COURTNEY FERREIRA, MS, RD, LDN

When it comes to research, the ability to conduct extremely controlled clinical studies can be incredibly impressive. Every day, researchers continue to challenge the status quo and answer new questions.

On the other hand, research is often biased.

It is impossible to get rid of all confounding variables that are out of the study’s control and may impact the results, and the findings presented to the public tend to be selective, and one reason the low-fat myth lives on. In some cases, diet trends attempt to leverage research to validate their approach to be the ‘best’ diet. However, we can’t always take what we read and hear as the absolute, especially when it comes to diet and health.

For example, let’s take a look at two separate studies on the health impact of keto diets.

As one of the most popular diet trends, a ketogenic diet is essentially an extremely low carbohydrate diet.  Think ~30 g per day, which is the equivalent of two pieces of fruit or 2 slices of bread.  The goal of a ketogenic diet is to restrict carbohydrates so much that the body switches to using other sources for energy. When this point is reached and maintained for some period of time (which can be different for everyone), the body goes into a state called ketosis which is best identified by urine ketone measurement.

It takes careful planning to follow this diet, and it is not the same thing as saying you are cutting out bread, pasta, and other high-density carbs. Fruits and vegetables are also sources of carbohydrates, but even these must be restricted to some degree in order to achieve ketosis.

The most common use of the ketogenic diet is in the management of epileptic seizures in children, and now adults.  The idea that this diet might offer health benefits to all individuals is widely disputed. Some people swear by this diet, boasting weight loss, improvement in blood lipid (cholesterol) profile and increased energy, while others say it is dangerous.

Of course, the research is just as conflicting. Let’s take a look.

Here are just two of many ketogenic diet studies that have been published over the last several years, and the results suggest different outcomes.

In Study #1, researchers put obese subjects on a ketogenic diet for 24 weeks. The subjects lost weight and showed significant improvements in their biochemical blood markers (including triglycerides, HDL and LDL cholesterol, and blood sugar). This study suggests that the ketogenic diet can be used safely for an extended period of time to improve weight and health of obese individuals.

In this more recent Study #2, a smaller sample size of obese and overweight men followed 4 weeks of a high carbohydrate diet and then 4 weeks of a ketogenic diet. The results were not as drastic as predicted. Researchers thought the ketogenic diet would lead to greater improvements in body composition and energy expenditure. The study found there was a small increase in metabolic rate after the ketogenic diet, but weight loss was comparable between the diets. This study concluded that the ketogenic diet did not induce greater weight loss than an equal-calorie, high-carbohydrate diet.

Depending on which study you read, your beliefs about this diet may likely be drastically different. You can argue for or against the ketogenic diet.

Study #1 indicates evidence that supports the ketogenic diet by showing long-term health benefits since people were on the diet longer, plus more subjects were in the study.  

One can argue that Study #2 did not show the expected benefits because subjects were given meals that were drastically different from their typical intake.  They also exercised, which led to comparable improvements from both types of diets, and did not perform the study long enough to allow the ketogenic diet to show its benefit. However, one can argue against the ketogenic diet and say just add exercise and cut back on portions to have improvements in weight and health.

Regardless of how you interpret these results, the consensus that it drives home is that self-education and, yes, even self-experimentation are the best resources you have for finding out what your best approach to weight loss and improved health is. In other words, if you hear about a weight loss approach, don’t take it as truth. Instead, look into the evidence for yourself.

Simply put, the best diet is one that works well and is sustainable for you. There is no perfect approach to a healthier lifestyle.

And remember, research disclaimers always indicate the need for more research as there is too much complexity when it comes to our body, metabolism, and weight loss. It is also important to note that the consensus of most health experts is that a varied, balanced diet incorporating all of your essential nutrients is still the key to healthy eating.

For example, a recent study evaluated the combined results across multiple diet studies and found that we can and should eat healthy fats in conjunction with protein and carbohydrates without the need to set limits. This study did not stress a specific, calculated regimen; rather, it suggested that the inclusion of more fat-rich foods such as fish, full fat dairy, oils, nuts and seeds can offer many health benefits. The best way to increase your healthy fat intake is to focus on whole, real foods, and cut back on the processed foods.

Everyone is different, but everyone can benefit from including more real foods into their day. While research is important and helps us move forward, take new findings with a grain of salt because there will always be research out there to contradict it.

Adapted from the original article.

Courtney Ferreira, MS, RD, LDN is a Registered Dietitian based in Baltimore, MD with a passion for helping individuals reach their health and wellness through flavorful whole foods and freedom from counting calories, fat, and minutes on a treadmill. For more insightful tips on living your healthiest life, visit Courtney at the RealFoodCourt.

1 Comment
  1. Not a bad write up, but the second study fails to account for the adaptation phase. So, if subjects ate carbs for one month and then switched to keto, they would maybe not even be adapted after 4 weeks. It takes a while for the body to adjust to a new fuel paradigm and in most cases, it’s been fueled by carbs for a long, long time. I eat a fair amount of plums and cantaloupe after exercise. I had zoodles tonight with celery, mushrooms, cheese and Italian sausage. Glucose was 82 an hour later. I HAD metabolic syndrome. I no longer do after 13 months of ketosis, several fasts and a new lease on life. All biomarkers for disease have improved. I’m part of the congregation and truly feel that most would benefit by eliminating all simple carbs. That being said, I like how you closed. Experiment and find out what works for you. No one gets out alive…

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