Hi all. I found this to be Dr. Mercola’s most comprehensive work. I summarize my big takeaways from this book - including what people here have been asking about 1) supplements 2) a summary of the book and 3) the biggest points. First, as you might guess from the title, I learned a lot about how our cells - and especially our mitochondria - play a big role in our energy levels. My doc already recommended I take KPAX Immune from Stanford U. for my fatigue, which overlaps with Mercola's mito supplement regimen, below, (whew) but we all need more than that. Our digestive system breaks down food into metabolites. Mitochondria are the little engines inside our cells that turn metabolites into a storable fuel called ATP. When they work well, we feel alert and strong; when they don’t, we get tired and run down. Mercola explains how what we EAT is a big, big deal. The details in these chapters are indispensable in my opinion but here's the gloss: Low in simple sugars, high in healthy fats. Excess carbs and sugars produce extra waste; no bueno. Healthy fats, like those from avocados or nuts, are the base materials for our body to produce hormones, which signal all sorts of processes. Mercola explains how protein takes more energy for your body to break down, which is great if you are watching your weight, and also prevents muscle loss as we age. Boom. Top foods: Wild-Caught Fatty Fish, Organic Leafy Greens, Cruciferous Vegetables, Avocados, Nuts and Seeds, Berries, Fermented Foods, Pasture-Raised Eggs, Grass-Fed Meats, Coconut Oil, Extra Virgin Olive Oil, and Bone Broth. Fasting. (I know it sounds terrible just wait). Most of us already do this when we sleep at night we just don't call it fasting. Intermittent fasting is simply extending that period a bit more (eat dinner early and/or breakfast late) - not as frightening as it sounds. Banger benefits - allows your cells to repair themselves. This process, autophagy, helps remove damaged parts from the cells. Regular fasting may help you improve energy levels too. Movement is another powerful tool. Activities like high-intensity interval training (HIIT) not only build muscle but also signal your body to heal. Just brisk walking can help, especially when combined with the above. Sunlight. Natural light, particularly near-infrared light, helps activate enzymes in the cells. Supplements can also help. For instance, CoQ10 is a nutrient that helps mitochondria make energy. Magnesium is vital - 50% of people are deficient!! Other supplements like alpha-lipoic acid, acetyl-L-carnitine, and N-acetyl cysteine help reduce cellular damage, help fight fatigue and boost immunity. If you don't want to buy dozens of these separately check out Stanford's KPAX Immune, Elysum Signal, and Integrative's Mitonutrients (that's mito- not micro-) Finally, processed foods, pesticides, and even certain types of radiation from everyday devices can stress our cells. Pretty simple overview here is keep a clean diet and limit exposure to unnecessary toxins. Dr. M’s approach to cellular health is about combining all of the above, not just one diet or pill or hack . I recommend reading the whole book, as there is far more detail than I can possibly cover here. Hope this helps get you started.