Why Food is More Than Fuel

In this blog, I’m sharing a full chapter from my book-in-progress, discover how food shapes energy, mood, and hormones beyond calories or willpower.

You’ve probably heard the phrase “food is fuel’’ and yes, whilst this is true, it barely scratches the surface of what’s happening.

Food isn’t just about calories or energy; it’s information, specifically a biochemical language your body understands. Every bite you eat sends messages, not just to your energy systems, but to your brain, your immune system, your hormones, your gut, and even your genes. Research in nutritional genomics has shown that food can literally switch genes on or off depending on what your body needs (Mishra et al., 2022). It’s a two-way conversation between your body and the world around you.

Depending on your relationship with food, this may feel inspiring, or maybe a little overwhelming. If you’ve been in survival mode, grabbing whatever’s on hand between meetings, fighting fatigue, and trying to hold everything together, the idea of food as “communication” might feel far away. But here’s the thing: your body is always listening, and it always responds.

Let’s Start with Energy

If you’re holding this book, chances are you’re not dealing with just a little tiredness. You’re probably navigating the kind of exhaustion that doesn’t shift with a nap, a coffee, or even a “healthy” smoothie. The kind that seeps into your mornings, fogs up your brain, and leaves you wondering whether this is just what adulthood is meant to feel like.

You’re not imagining it. And no, you’re not lazy.

Your body creates energy in the form of ATP (adenosine triphosphate), made inside your mitochondria, the tiny, battery-like powerhouses in every cell. They take the food you eat and turn it into usable energy for everything you do, from brain activity to hormone production to movement (Vyas et al., 2024).

To do this well, your body needs raw materials:

● Glucose from carbohydrates

● Amino acids from protein

● Fatty acids from healthy fats

● Micronutrients like magnesium, B vitamins (especially B2, B3, B5), iron, CoQ10, and selenium

Even a small deficiency in one of these nutrients can create a bottleneck in energy production. Magnesium, for example, is required in more than 300 different processes in the body, including the steps your mitochondria use to make energy. Yet national surveys have found that average intakes in many women and teenagers often fall below recommended levels (UKHSA & FSA, 2024).

When mitochondria don’t have what they need, or they’re overwhelmed by inflammation and stress, your energy levels drop. The result? Symptoms like:

• Brain fog

● PMS or irregular periods

● Digestive sluggishness

● Mood dips or anxiety

● Low motivation or burnout

These aren’t random annoyances. They’re early warning signs that your body is struggling. Even your hormones depend on energy and raw materials to be made properly. Oestrogen, progesterone, and testosterone all require cholesterol plus specific vitamins and minerals to be produced. If resources are scarce, your body will prioritise survival over things like reproduction and repair. That’s why low energy, irregular cycles, and low libido often show up together.

You can’t hustle your way out of cellular depletion. But you can start to rebuild, slowly, gently, and consistently, by giving your body what it truly needs.

🔍 Try This: Keep a simple food-and-energy journal for 3 days. Notice what you eat, and how you feel 1–2 hours later. Do you crash after a carb-heavy snack? Do you feel clearer after a protein-rich meal? Clues live in the patterns.

Beyond Weight: What Food Really Impacts

For many of us, “eating well” was framed around weight, but food is about so much more than the number on a scale. Let’s reframe that health is not your dress size, and your weight is not the best barometer for energy, resilience, or hormone balance.

Food affects how you function. It shapes the internal terrain of your body in ways that show up in how you feel day to day. For example:

• Mood and focus: Research shows that nutrient deficits and blood sugar swings affect neurotransmitter production, leaving you feeling foggy or irritable (Benton, 2008).

• Immune health: Around 70% of your immune system sits in your gut, directly influenced by what you eat and how your microbiome is functioning (Belkaid & Hand, 2014).

• Hormones: Nutrients like zinc, B6, magnesium, protein, and healthy fats are essential building blocks for everything from ovulation to adrenal balance to thyroid function.

• Detox and recovery: Your liver relies on antioxidants, amino acids, and sulphur-rich foods (like broccoli and garlic) to clear toxins and excess hormones.

Instead of asking, “Will this help me lose weight?” try asking, “Will this help me feel calmer, clearer, and stronger tomorrow?”

The Problem with Convenience Food

Here’s the challenge: our modern food system wasn’t built for human thriving. It was built for profit.

Ultra-processed foods, the snack bars, flavoured yoghurts, ready meals, and so-called “healthy” drinks on supermarket shelves, are designed to be cheap, convenient, and addictive. In Ultra-Processed People, Dr. Chris van Tulleken (van Tulleken, 2023) describes them as “food-like substances” that trick your brain into wanting more, even when your body is undernourished.

In fact, a study from the National Institutes of Health found that people eating diets high in ultra-processed foods consumed over 500 extra calories per day compared with those eating whole foods, even though meals were matched for satisfaction and macronutrients (Hall et al., 2019).

And it’s not just about calories. UPFs often contain emulsifiers, artificial sweeteners, and refined oils. Early research suggests these may disrupt gut bacteria, affect appetite regulation, and promote inflammation (Schnabel et al., 2019; Chassaing et al., 2015).

But here’s the important bit: this isn’t about shame. Access, time, money, and capacity all shape your choices. Sometimes the most supportive thing is the quickest option you can manage, and that’s okay. The invitation isn’t perfection; it’s intention. Choosing real food where and when you can.

🔍 Action Step: Swap one ultra-processed snack this week for a whole-food option, like apple slices with nut butter or oatcakes with boiled eggs. Small shifts compound into bigger change.

Food Affects Every System

Here’s a quick snapshot of how whole, nutrient-dense food supports the systems most connected to energy and hormone balance:

● Gut: A fibre-rich, plant-diverse diet feeds beneficial bacteria that support digestion, hormone metabolism, and even neurotransmitter production (Cryan et al., 2019). Alcohol, sugar, lack of sleep, ultra-processed foods, and stress can disrupt this balance.

● Liver: Processes toxins, hormones, and metabolic byproducts, think of it as your detox hub. It thrives on sulphur-rich vegetables (like onions, garlic, and broccoli), bitter greens, and antioxidants (milk thistle, turmeric).

● Thyroid: Needs selenium (from Brazil nuts), iodine (from seaweed or iodised salt), zinc, and iron to produce and convert hormones. Subtle nutrient depletion here can lead to sluggish metabolism and fatigue (Zimmermann & Boelaert, 2015).

● Brain: Requires omega-3s, stable blood sugar, B vitamins, and choline (from eggs, liver, or lecithin). Deficiency in any of these may impair focus, memory, and emotional regulation (Gómez-Pinilla, 2008).

Eating Well Is Emotional

If you’re skipping meals, snacking in the car, or collapsing into sugar cravings at 4pm, it’s not because you’re undisciplined. It’s because you’re likely in survival mode.

How we eat reflects how we feel. But it also shapes how we feel.

When you begin to eat with intention, not control, but with kindness, you send a powerful message to your nervous system: “I am safe. I matter.” That message ripples outward, into your hormones, your mood, your energy, and even your sense of self.

You don’t need a perfect food plan. You need a relationship with food that supports you. One that feels sustainable, kind, and rooted in respect, not restriction.

🔍 Try This: Before each meal, instead of asking, “Is this healthy?” try asking, “Is this supportive?” That one shift can change the entire experience of eating.

Let’s Reflect

• What do you notice about your energy after different meals or snacks?

• Do you get an afternoon slump? What do you usually reach for?

• What one food upgrade could you try this week that feels both doable and kind?

Key Takeaways

• Food is information. It guides your genes, energy systems, and resilience.

• Mitochondria need support. Whole foods + micronutrients keep your “cell batteries” working.

• UPFs override biology. Controlled trials show they drive overeating and energy crashes.

• Your gut is immune-central. What you eat directly shapes ~70% of your immune system.

• Eating well is self-respect. This isn’t about perfection; it’s about support, capacity, and care.

You belong at the table. And you deserve to eat like someone who deserves to feel well.

References

• Belkaid, Y., & Hand, T. W. (2014). Role of the microbiota in immunity and inflammation. Cell, 157(1), 121–141.

• Benton, D. (2008). Micronutrient status, cognition and behavioral problems in childhood. European Journal of Nutrition, 47(S3), 38–50.

• Chassaing, B., et al. (2015). Dietary emulsifiers impact the mouse gut microbiota promoting colitis and metabolic syndrome. Nature, 519(7541), 92–96.

• Cryan, J. F., et al. (2019). The microbiota-gut-brain axis. Physiological Reviews, 99(4), 1877–2013.

• Gómez-Pinilla, F. (2008). Brain foods: the effects of nutrients on brain function. Nature Reviews Neuroscience, 9(7), 568–578.

• Hall, K. D., et al. (2019). Ultra-processed diets cause excess calorie intake and weight gain. Cell Metabolism, 30(1), 67–77.

• Mishra, U.N. et al. (2022) “Nutrigenomics: An inimitable interaction amid genomics, nutrition and health,” Innovative Food Science & Emerging Technologies, 82, p. 103196.

• Schnabel, L., et al. (2019). Association between ultra-processed food consumption and risk of mortality among middle-aged adults: a cohort study. JAMA Intern Med, 180(2), 283–291.

• UKHSA & FSA. (2024). National Diet and Nutrition Survey: Rolling Programme Years 12–16 (2019 to 2024).

• Van Tulleken, C., 2023. Ultra-Processed People: Why Do We All Eat Stuff That Isn’t Food—and Why Can’t We Stop? Cornerstone Press.

• Vyas, C. M., et al. (2024). Mitochondria: At the crossroads of health and disease. Cell, 187(2), 294–316.

• Zimmermann, M. B., & Boelaert, K. (2015). Iodine deficiency and thyroid disorders. The Lancet Diabetes & Endocrinology, 3(4), 286–295.

About Claire

Claire Thomas is a Nutritional Therapist, NLP Practitioner, and Phlebotomist with a background in Children’s Nursing. She specialises in supporting ambitious women who feel exhausted, burnt out, or stuck in survival mode. Through personalised nutrition, mindset coaching, and functional testing, Claire helps her clients increase their energy levels, find clarity, and feel like themselves again. Based in Tiverton, Devon, she works both in-person and online through her clinic, Nourish to Soar

Categories: : boost your energy, eating well, energy levels