#198: Tommy Wood, MD, PhD: Gut Health & Bacterial Diversity on a Ketogenic Diet

by Deanna Mutzel, DC

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About Tommy Wood, MD, PhD

Dr. Wood is a qualified medical doctor, graduating from Oxford University in 2011. He has a Bachelors degree in Natural Sciences and Biochemistry from Cambridge University. After working as a junior doctor in the UK for two years, Tommy is completing a PhD in neonatal brain metabolism at the University of Oslo, Norway and is an experienced rowing and strength coach, and have written and lectured on the multiple beneficial effects that optimal movement can have on both health and performance.

Dr. Wood is the Chief Medical Officer of Nourish Balance Thrive


Show Notes


02:12 How Keto Goes Wrong: People are generally happy with ketogenic/low carb diets at first. The health of your gut plays a part with whether the diet brings optimal health. If you have a dysbiotic or inflamed gut, you will have an upregulation of certain enzymes that will prevent you from detoxing through the bile pathway, so you reabsorb the toxins.

04:03 Western Diet’s Effect upon the Microbiome: With a western diet, you have a decrease in bifidobacterium, which are integral in ensuring a healthy gut lining.. Inflammation in the gut feeds e coli and other oxygen-loving bacterium. Inflammation changes the way the cells in your gut respire, so they no longer perform fat oxidation.

05:00 Metabolic Endotoxemia: Toxins sit in the outside layer of gram negative bacterium and proteus bacterium, which are meant to be in small numbers in our gut. High numbers of these cause inflammation and insulin resistance. Refined liquid fat is an excellent transport mechanism for these toxins. Every meal you eat causes some level of inflammation. You are exposing your body to the outside environment through the gut. The higher the level of endotoxin exposure, the higher the insulin response. Your body raises insulin levels in an attempt to divert nutrients to the immune system to deal with the bugs.

09:28 Treating Endotoxemia in the Insulin Resistant: Cutting down on carbs benefits insulin resistance. When someone who is obese or over weight loses weight, endotoxemia is improved. Metformin improves the integrity of gut lining and reduces the signaling you receive from the receptors that respond to endotoxin, and it shifts the gut microbiome.

10:18 Insulin and Chronic Inflammation: Insulin helps divert energy to the immune system. Insulin activates and deactivates the immune system. It has an antioxidant effect and an anti-inflammatory effect. Constantly elevated insulin from your diet, sleep deprivation or stress, causes an imbalance. That ability for insulin to turn off the immune response are down regulated and pro-inflammatory responses are upregulated. Chronic inflammatory disease causes this imbalance in insulin.

13:51 Liquid Fats: Our ancestors did not have refined liquid fats. Occasionally, Dr. Wood uses organic heavy cream, which contains proteins that are lost in butter. He mixes them with egg yolks and MCT oil. Fatty coffees contain a lot of calories and not much nutrition.

17:04 Keep the Fiber: When people decrease carbs, they may decrease fiber, which is important for microbiome health. Dr. Wood has used a mixture of non-starch polysaccharides to boost bifidobacterium and other butyrate producing bacteria. In general, though, he encourages people to eat more plants. You can stay keto/low carb while eating a variety of vegetables. Dr. Wood does not worry about the carbs in berries.

19:08 Dr. Wood’s Green Tea: Dr. Wood recommends to his MS patients that they eat Nordic blueberries to help heal the blood brain barrier. He created a hot beverage with matcha, green tea, turmeric, bilberry extract, grape seed extract, broccoli seeds and black pepper. It is well liked, so it will likely be produced to sell.

20:46 Bacterial Diversity: In general, people with metabolic disease, obesity and insulin resistance, have a reduced microbial diversity. Those of us on a ketogenic diet may be lacking in diversity in our foods. For patients with very little diversity, Dr. Wood has sometimes put them on a high carb vegan diet to force them to eat more plants and force a shift in the gut microbiome.

24:01 Nourish Balance Thrive Online Clinic: Dr. Wood is the medical director for this online program, developed by Christopher Kelly, to help athletes’ improve their health.

27:09 Flexible Carbohydrate Intake with Exercise: High intensity athletes find that ketogenic diets work well at the start, but things start to fall apart because they are not fueling their glycolytic activities. Thyroid hormone drops. Testosterone drops. Libido drops. A middle ground would help, possibly through carb cycling. Metabolic flexibility allows athletes to use whatever substrate is best at the right time. When you are keto, you are performing gluconeogenesis all the time, just not fast enough for some athletic activities. In some circumstances, you get a better benefit from ketone esters as an exogenous fuel source if you also take an anaplerotic substrate glucose at the same time, fueling both pathways.

38:08 Water Retention: For weight lifters, water retention within the muscle provides a strength benefit. One gram of glycogen comes with 3 to 4 grams of water. We have up to 500 grams of glycogen. When you overfeed on carbohydrates, you can stuff more glycogen, which will include more water. Some famous body builders are generally low carb or keto, but they will manipulate carbohydrates to get the look they want at the time that they need it.

41:15 Maintaining Muscle Mass on a Ketogenic Diet: To achieve a pure anabolic response, having higher spikes in insulin could be beneficial. The data on muscle adaptation to resistance exercise finds that being low carb does not hinder it, as long as protein intake is adequate,. Restricting your eating window, reducing protein intake and reducing carbohydrate intake done together may cause issues with muscle growth. Being keto reduces hunger, making it more challenging to eat the calories needed. The most important part of putting on muscle is consistently getting into the gym, doing the right kind of training and recovering from it. For longevity, strength is more important than the size of muscle. Eat to fuel your goals.

45:02 Ketosis and Hormones: Leptin and insulin are our short term and long term energy sensing hormones. They are closely tied to reproductive function. High cortisol and low leptin will signal your HPG axis to dampen testosterone as a preservation strategy, to be ramped up with stress is lower and food intake is higher.

46:59 Chronically Low Insulin: Insulin/glucose is needed to regenerate glutathione. The pentose phosphate pathway uses glucose as the starting point. Through this pathway insulin fluxes and regenerates antioxidants. People who exercise more than 6 hours per week have lower glutathione levels than people who exercise fewer hours per week. Help is needed to boost the pathway. There is a a high antioxidant and high insulin demand from exercise or chronic inflammatory condition like autoimmune disease.

49:35 Food Processing Alters Insulin Release: The amount that you grind your carbohydrate or protein dramatically increases your insulin response, despite having no effect upon macronutrients. Smoothies effect glycemic response versus consuming the whole ingredients. Stay away from keto or paleo junk food.

52:16 Dr. Wood’s Morning Routine: First thing in the morning, he walks the dog barefoot. It is important for him to touch the earth first thing in the morning. He makes coffee and a smoothie. The smoothie is a way to eat plants in the morning. The off cuts of vegetables throughout the week go into a bag in the freezer to be used for soup or smoothies. When he starts working from home full time, there are numerous things like meditation that he plans to include.

54:54 Dr. Wood’s Research: His PhD was in neonatal neuroprotection for newborns with brain damage. They are treated with therapeutic hypothermia. Now he is researching treatments for brain injuries in babies born prematurely.

55:57 Dr. Wood’s Favorite Herb: If stranded on a desert island, he would take silasibin mushrooms. The silasibin in small doses would help with any depression from being isolated on the island. A large dose could be used to end it all in a massive trip.

57:05 Dr. Wood’s Elevator Pitch: He would give a lesson in evidence based medicine. Fixing stress, sleep, diet and gut will never be done as a trial. It doesn’t fit into the traditional model of evidence based medicine, but it is what we need to do to fix people.


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