Why High Levels of Ketones Does Not Equal Greater Weight Loss

 In Nutrition

In a previous posting, I spoke through the different ways in which you can measure the level of ketosis in the body. One of the points that I brought up is this notion that exists in the keto world of people being told or believing that a higher ketone reading automatically means you will experience a greater rate of weight loss.

The point I stated before and I want to repeat again is a classic misinterpretation of cause and effect in that:

“Just because you have a high ketone level in the body, does not mean that you will automatically experience a fat/weight loss.”

I’ve been working with the application of a ketogenic diet for over 8 years now and where this notion came that high ketones=greater weight loss, I’m not too sure. Over the past couple of years though with the explosion in the popularity of a ketogenic diet, it is becoming more prolific especially amongst many keto online groups.

I have had clients come to me in the past before looking for help with their diet. They have followed many “experts” advice online and it has lead them down a path of believing that the only way to success with this form of diet is all about upping the fat, driving the carbs and the protein down as much as you can.

Some people coming to me were consuming as much as 80% or even 90% of their diet as fat. Now unless you have a specific therapeutic reason for following a ketogenic diet or if you really feel like that is the optimal diet for you, not many people need to be eating this much fat.

Also, if you are someone that is looking to follow this diet especially for weight loss, then I promise you, adding more fat above what your body needs is going to cause you to gain, not lose weight.

Where I really see this occurring, is when people are struggling to lose weight or they have hit a weight loss plateau. Then the advice of “up the fats to get ketone levels up” seem to come out.

Why high ketones don’t always equal weight loss- The evidence

If we take a face value look at the evidence that exists comparing low carbohydrate and low fat diets on the rate of weight loss, there is now a lot of evidence to show that the low carbohydrate diet will often win out (1). Although the ketosis level is believed to play a factor in this, can it directly be correlated to the weight and fat loss?

Well, if we look at the data for those participants in the low carb arms of these studies, we can start to get a little picture of what is happening. In one study that looked to compare a low carb diet vs a low fat diet in healthy women, they reported that those in the low carb diet reported a statistically significant greater weight loss (2). When we take a look at the weight loss and the corresponding beta-hydroxybutyrate levels (BHB; one of 3 ketone bodies) however, we see at 3 months the BHB level was at 1.10mmol/L but at 6 months it dropped to 0.5mmol/L. From baseline to the 6 months point though the participants continued to lose weight and fat mass even though the ketone level appeared to drop.

This has been highlighted in other studies, where by the rate of weight loss in the low carbohydrate group continues from the start up to 6 months, again independent of urinary ketones dropping (3).

On the flip side of this, a poignant study that came out in 2008 which compared the low fat, Mediterranean and low carb diet, showed that the low carb diet won out in many outcomes, including that of rate of weight loss at 2 years (4).

When we look at the rate of weight loss though, although by the 2 years’ participants in the low carb arm had lost around 5kg, at 6 months they had lost a total of 7kg. What was interesting again to note is that their ketone levels at 24 months was still raised in comparison to the beginning. Therefore, if the theory is that the higher the ketone level equals the greater rate of weight loss, shouldn’t the weight continue to go down and not rebound back up?

The Take-Home Message:

The fact of the matter is, no matter what weight loss tool or approach you use, changing your lifestyle, losing and maintaining a weight loss is not an easy thing to do.

Whilst the evidence shows that following a low carbohydrate diet does appear to win out over other dietary approaches, this cannot be attributed purely to the ketone levels. In that adding in a bunch of fat, or taking a ton of exogenous ketones to get your ketone levels up could be counterintuitive when trying to achieve and promote a fat loss in the body.

The specific reasons that the ketosis may be having an impact may have a lot more to do with its impact on appetite and hunger control which subsequently results in an overall lower intake in general.

It is my theory that not everyone needs to be following a ketogenic approach for weight loss. Some people could fair well on a standard low carbohydrate approach. The next time someone gives you the advice to up your ketones to increase the fat loss, please stop and think twice, as you may end up doing yourself more harm than good.

The reality is that there are a ton of factors that can prevent and stall weight loss (again I will cover these in future posts), independent of ketosis.

Finding a dietary approach that works for you and using it as a template that you can build and grow on is the only tool that will work in the long run.

I would love to hear your thoughts and experiences with a ketogenic diet and what has and hasn’t worked for you.