Dr. Brianna Stubbs is the Research Lead here at H.V.M.N. She worked on the groundbreaking “Cell Metabolism” paper, which studied the effects of BHB ketone ester (the ketone body in H.V.M.N. Ketone) on elite athletes, including cyclists and rowers. She’s one of the foremost minds on ketones.

Now we’re opening her office door to you. Welcome to Office Hours with Dr. Brianna Stubbs.

A few weeks back, we issued a call for questions in the H.V.M.N. Newsletter. We received an overwhelming number of responses and wish we could've answered them all.

We appreciated all the questions and encourage you to keep asking them. H.V.M.N. is part of a larger community of athletes and biohackers and nutritionists, and we all want to learn together.

"What types of carbs are best to pair with H.V.M.N. Ketone before and during prolonged endurance exercise, like a marathon or race?"

Dr. Stubbs: Athletes eating a normal diet can use H.V.M.N. Ketone before races alongside their usual carbs. Of course, individual habits vary, but the aim is to ensure you have plenty of stored muscle glycogen prior to a race. People tend to eat meals based around the slow release of carbs the night before (pasta, baked potato), and morning of (oatmeal, bagel), a race.

During races, athletes eat foods for the fast release of carbs. This typically is an energy drink or gel. These products contain something called “multiple transportable carbohydrates,” which means they’re easier for the gut to absorb during exercise. It’s common for athletes to experience gastrointestinal issues (GI) in long races, so there’s a fear getting enough carbs may have a negative result in that regard.

People eating keto sometimes “carb up” before events, and continue consuming carbs during races. The sources and amounts of those carbs vary by person.

One well known fat-adapted athlete, Zach Bitter, describes his fueling strategy around racing as such: “The last couple days involve taking in some of my favorite concentrated carbohydrate sources. I don't consume them in isolation, but instead in combination with a good fat and protein source. This allows me to top off my glycogen, but not to the degree that it sabotages fat being my primary fuel source. The morning before the race I revert back to very low carbohydrate intake so fat is my primary energy source. Then I slowly trickle in carbohydrate throughout the event. My target range during the race itself is between 150-250 calories per hour depending on intensity.”

Zach’s pre-race carb sources are raw honey, sweet potato, red potato (cooled), granny smith apple, berries, melon, fermented organic non-GMO corn. His racing carb sources include banana chips (cooked in MCTs), potato chips, gels, M&Ms.

"What impact does black coffee have on fasting?"

Dr. Stubbs: The question around black coffee and fasting has received a lot of attention recently. Answers change depending on who’s asked.

Coffee doesn’t contain calories, so in that regard, it wouldn’t count as breaking a fast. However, coffee contains caffeine and other polyphenols, which likely have an array of effects we don’t fully understand yet–so some may alter the process of a fast.

Recently, caffeine was shown to increase autophagy, and ketogenesis. Negative effects should be marginal. Timing caffeine intake for earlier in the day (and during daylight hours) may minimize the effects on circadian rhythms if you were really concerned. I drink black coffee during all my fasts.

"Regarding long-term ketone use, are there any concerns about safety, consequences or continued efficacy? What about safety concerns using ketone when NOT on a low-carbohydrate diet?"

Dr. Stubbs: In order for H.V.M.N. Ketone to receive FDA GRAS “food ingredient” status, it needed to demonstrate a high level of safety. Therefore, there should be no issues associated with long-term use. Ketones are a natural molecule that our bodies can make and utilize. Many people follow a ketogenic diet for years with no adverse effects, so if used within the guidelines, having high BHB from ketones should be safe.

We haven’t studied the long-term efficacy of ketone esters with regards to specific endpoints like achieving the same level of blood ketones, impact on performance, or continued subjective feeling. Looking at ketones as a macronutrient (like carbs), we shouldn’t expect to see declining effects over time–using carbs to boost race performance should provide the same benefit consistently (as long as they aren’t overused). It’s possible the body optimizes the ability to burn ketones if regularly used, but no experiments have directly addressed this.

People often ask about the safety of consuming ketones concurrently with carbs. First, it’s important to point out long-term energy excess (coming from any macronutrient) is not optimal for health. With that in mind, as long as the body is in energy balance, there shouldn’t be detrimental effects of having both ketones and glucose in the system at one time.

A healthy body is constantly making adjustments to ensure our cells are not overloaded with nutrients. For example: when carbs are consumed, insulin is released. This lowers the release of glucose from the liver, and the release of fat from the fat cells, to allow the body to get more energy from the carbs it has just consumed.

When consuming ketones, there is a similar effect: blood glucose drops,, and so does blood fats. This means the cells are not overloaded with nutrients. On a cellular level, ketones are able to slow down the flux of carbs into the Krebs Cycle, making sure it’s not overloaded.

"Is the keto diet hard on the liver?"

Dr. Stubbs: No! Evidence suggests that, for many people, eating a ketogenic diet can improve liver health.,

The rationale for keto being hard on the liver is that high levels of fat in the blood can accumulate in the liver and cause fatty acid liver disease. The liver is the main site of ketone production, so people may worry that asking it to do the extra work of making ketones may be harmful.

However, studies of the ketogenic diet have shown that it can reduce fat accumulation in the liver and reduce markers of liver damage measured in the blood.

"Are there any studies or anecdotal evidence that ketone esters can help ease alcohol withdrawal?"

Dr. Stubbs: This is an area we are actively researching. One of the the hypothesised issues occuring during alcoholism is that the brain begins to get accustomed to some of its energy coming from by-products of alcohol breakdown (for example, the ketone body acetone) and less from glucose.

So cutting back on alcohol leads to lack of energy in the brain. It has been shown in animal studies that feeding them a ketogenic diet during the withdrawal phase can decrease some of the behavioral symptoms, possibly because the ketones can provide extra fuel for the brain. It’s possible ketone ester drinks could have this same effect.

Thanks for stopping by the office. If you have any other questions, reach out to care@hvmn.com and we'll try to provide an answer next time.