Mitochondrial Health: A Clinical Nutritionist's Guide to Energy (2026)

You wake up after a full night's sleep and still feel flat. Coffee helps for an hour. By 3pm you are running on willpower. Most of us have been there, and a lot of the internet's answer is a supplement, a special water or an extreme diet.

Underneath that tiredness sit your mitochondria, the tiny structures inside nearly every cell that turn food and oxygen into usable energy. This guide covers what they do, what wears them down, what the evidence says helps, and where popular ideas such as deuterium-depleted water and the carnivore diet sit on the evidence scale. I have been working in nutrition and lifestyle medicine for about 30 years, and my aim is simple: tell you what is promising, what is unproven, and what I would actually do.

What mitochondria actually do

Mitochondria are often called the powerhouses of the cell, and for once the cliché is fair. They take the products of the food you eat and, using oxygen, make a molecule called ATP, the form of energy your cells spend on everything from muscle contraction to thinking.

A few facts worth knowing:

• Cells with high energy demands, such as heart, brain and muscle cells, contain far more mitochondria than others.
• Mitochondria have their own small set of DNA, passed down from your mother.
• They also take part in calcium handling, heat production and signalling that decides whether a cell repairs itself or retires.

Mitochondrial function tends to decline with age, and changes in it are being studied in areas such as metabolic disease, neurodegeneration and exercise capacity. That research is active and still developing, which is a good reason to be wary of anyone promising a simple fix.

What puts pressure on your mitochondria

Think of the main stressors as a mismatch between the load placed on your cells and the conditions they need to cope.

• Inactivity. Muscle that is rarely challenged tends to carry fewer and less efficient mitochondria.
• Chronic energy excess. Constantly high intake of refined carbohydrate and fat, with little movement, keeps the system oversupplied.
• Poor or short sleep. Sleep is when much cellular maintenance happens.
• Ongoing stress. Long periods of stress hormones alter how your body uses fuel and recovers.
• Alcohol and smoking. Both add to oxidative stress.
• Nutrient gaps. Several vitamins and minerals are needed to run the energy machinery.

What helps: the foundations

1. Move your muscles, often

Regular exercise is the best-supported way to improve mitochondrial capacity in humans. Both endurance and strength training help, and so does simply breaking up long sitting. You do not need extremes. Consistency beats intensity for most people.

2. Eat enough protein and a wide range of whole foods

Your mitochondria rely on a team of nutrients, including B vitamins, iron, magnesium, zinc, selenium, carnitine and coenzyme Q10. A varied whole-food diet with quality protein, vegetables, healthy fats and a mix of animal and plant foods covers most of them. If you want to go deeper on food structure, see our article on macros, seasons and light.

3. Protect your sleep

Sleep is not a luxury for energy. Regular sleep and wake times, a dark cool room and winding down from screens all support the repair work that happens overnight.

4. Get outside early

Morning daylight helps set your body clock, which in turn influences sleep, hormones and how you use energy during the day. Some early research is looking at specific wavelengths of light and mitochondria directly, but the strong, practical evidence is for daylight and your body clock. It is free, and it is the easiest habit on this list to start tomorrow.

5. Give your body an off switch

Our bodies cope well with cycles of effort and rest, feeding and not feeding. A gap of 12 to 14 hours overnight without food suits many people. Longer is not better for most: see why longer fasting is not better for your health.

Where deuterium fits

Deuterium is a naturally occurring heavier form of hydrogen. It makes up roughly 150 parts per million of hydrogen in ordinary water, and it is present in the food we eat. Some researchers have proposed that lowering the deuterium load, through deuterium-depleted water or a lower-deuterium diet, may influence mitochondrial energy production and metabolic health.

Here is where the evidence stands. Published reviews describe possible benefits in areas such as blood sugar control, mood and sport performance, but much of the underlying human data comes from small or early studies, often with different methods and water concentrations, so it is hard to draw firm conclusions. Larger, well-controlled human trials are still needed. Deuterium-depleted water is also expensive.

My view: it is a reasonable topic for curiosity, but not a reason to buy specialty water before the basics are in place. If you want to explore it, start with the foundations above and read our article on deuterium water, health impacts and mitigation strategies.

Where the carnivore diet fits

Diets built mainly on animal foods supply plenty of nutrients that mitochondria use, including carnitine, coenzyme Q10, iron and B12. Some people report steadier energy. But there are no long-term trials on the carnivore diet itself, it provides little or no fibre, and in some people it raises LDL cholesterol. A lot of the same benefit can usually be had from a whole-food diet that includes quality animal foods alongside vegetables and other plants.

If you are curious, talk to a professional first, particularly if you have kidney disease, heart disease, high cholesterol, take medication, are pregnant or breastfeeding, or have a history of disordered eating. Our article, Enhancing Mitochondrial Efficiency through the Carnivore Diet, goes through the nutrients and the limits of the evidence.

Signs your energy problem might need a closer look

Persistent tiredness is common and has many causes. Before pointing the finger at mitochondria, it is worth ruling out things your GP can test, such as low iron or ferritin, low B12, thyroid problems, blood sugar issues, sleep apnoea, depression and medication effects. True mitochondrial disease is a rare genetic condition and is diagnosed by specialists, which is a different thing from everyday low energy.

See a doctor promptly if your fatigue is severe, comes with unexplained weight loss, muscle weakness, shortness of breath, chest pain, or has lasted for weeks without explanation. A helpful starting point for tracking your numbers is our article on which markers matter most.

A simple two-week energy reset

1. Walk outside within an hour of waking, for 10 to 15 minutes.
2. Add a palm-sized serve of protein to breakfast.
3. Move your body in some way every day, including two short strength sessions a week.
4. Finish eating about three hours before bed, and keep a regular bedtime.
5. Note your energy out of 10 at midday and 4pm. Review the pattern after two weeks.

If energy has not shifted after a fortnight, that is useful information, and a good point to get personalised support and some testing.

Frequently asked questions

What are mitochondria in simple terms?

They are small structures inside your cells that convert food and oxygen into ATP, the energy your cells use to function.

How can I improve my mitochondrial health naturally?

The best-supported steps are regular exercise, a varied whole-food diet with enough protein, good sleep, morning daylight and managing stress.

Is deuterium-depleted water worth buying?

The evidence is early and mostly from small studies, so it is not a proven benefit. Get the foundations right first.

Is the carnivore diet good for mitochondria?

It supplies nutrients mitochondria use, but there are no long-term trials and it can carry risks. A balanced whole-food diet is a safer starting point for most people.

What are the signs of poor mitochondrial function?

Persistent fatigue, poor exercise recovery and brain fog are common, but these signs are not specific. Speak with your GP to rule out other causes.

Do supplements like CoQ10 help?

They may help some people in specific situations, but they are not a substitute for the basics. Discuss supplements with a qualified professional, especially if you take medication.

Next step

If you would like help working out what is behind your energy and what to do about it, book a free 15-minute clarity call. We can talk through your history and decide whether testing or a personalised plan makes sense. Consultations are also available online.

About the author. Anthony Hartcher is a clinical nutritionist, lifestyle medicine specialist and science educator with about 30 years of professional experience. He holds a Bachelor of Engineering (Hons) in Chemical Engineering, a health science degree majoring in nutrition and dietetic medicine, and a degree in complementary medicine. He runs me&my wellness in Randwick, Sydney.

This article is general information and not a substitute for personal medical advice. Speak with your doctor before changing your diet or starting supplements.