How to be fuelled, not fatigued, by food

By The Gut Health Doctor Team

Dr Megan Rossi in a lab looking through a microscope

Being energetic can often feel like a complicated thing to achieve as it’s impacted by so many influences.

From what you eat, to how much (or how little), lifestyle factors, blood sugar and nutrient levels, metabolism, hormones and many other factors. Not forgetting your gut microbiota and the health of your gut. But rest assured this blog has you covered.

The main provider of energy is food and although all foods provide energy, not all foods impact energy levels in the same way. This blog will explore how your food choices could influence whether you feel fuelled or fatigued by the food you’re eating and how you can support your energy levels through some small dietary tweaks!

It’s worth becoming more mindful of how you feel energy wise. Make a note of when this dips or rises and see if you can pin this down using the six principle laid out in this blog. Our energy impacts our relationships, activity levels and work, so it’s worth getting savvy on.

6 tips on how to eat for energy

A white wooden board with bread, bananas, pasta and also rice, lentils and chickpeas in small wooden bowls displayed

1. Prioritise complex carbs

The main function of carbohydrates is to provide us and our gut microbes with energy. When we eat carbohydrates, they are broken down into glucose (aka sugar) units, with the exception of fibre which is broken down by our gut bacteria. There are two main categories of carbohydrates; simple and complex carbs.

  • True to the name, simple carbohydrates are easily broken down. Foods rich in simple carbohydrates (like chocolate, biscuits, sweets, sugary cereal and white bread) provide energy quite quickly but the energy is not long lasting and so can lead to a ‘crash’ shortly afterwards. Although there’s no reason to completely eliminate from your diet, relying on simple carbohydrates for energy tends to lead to a viscous cycle of energy highs and lows – which we want to avoid!
  • Complex carbs, as you may guess, take a little longer to break down which means that the energy is slower to release and is therefore longer lasting. These carbohydrates include foods like oats, quinoa, barley etc. and root vegetables like sweet potato. Complex carbs are typically a valuable source of fibre too, which will feed our hungry gut microbiota (GM) – win-win!

2. Consider your portion sizes

Ever felt tired and sluggish after a large meal? The bigger your portion, the more blood tends to divert away from other organs and into your intestine. This can slow down your other bodily processes, leading to issues like fatigue.

A study published in the Journal of Physiology and Behaviour found that the digestion of high-fat meals leads to the release of the hormone cholecystokinin (CCK), which can contribute to feeling tried after a meal.

Try splitting meals into smaller portions particularly those that are higher in carbohydrates or fats.

A glass bowl with a spoon filled with yogurt with granola, nuts and blueberries

3. Make your snacks smart

Snacks can top up energy levels in between meals helping us to avoid those pesky energy dips (like that famous 3pm slump!). When we combine carbohydrates with protein or a healthy fat, it can slow down the release of energy which keeps energy levels stable and leaves us feeling satiated for longer. This in turn prevents mindless grazing and the chances of overeating at subsequent meals.

Ensure to include snacks that are rich in fibre, healthy fats and/ or some protein such as:

  • Seeded sourdough with tzatziki and tomato
  • Live yogurt with sliced pear
  • An orange and small handful of mixed raw nuts
  • Homemade popcorn with a drizzle of extra virgin olive oil and a small pinch of salt
  • Wholegrain crackers with hummus and tomato

4. Have caffeine in the morning

It’s well known that coffee can help improve alternes and fight fatigue thanks to its caffeine content and it’s also is a great source of antioxidants and polyphenols, which are beneficial plant compounds. A study published in the journal Nutrients in 2020 found that regular coffee consumption was associated with higher levels of Bacteroides, which are a beneficial group of bacteria found within our GM.

However, there can be too much of a good thing and coffee (namely the caffeine component) can impact sleep quantity and quality; which in turn impacts our overall energy levels. A study published in the Journal of Clinical Sleep Medicine found that consuming 400mg of caffeine 6 hours before bed may delay sleep by over an hour.

With this in mind, it’s a good idea to keep caffeine consumption for the morning so that it doesn’t interfere with sleep. Switching to decaf coffee and herbal teas (although note that green tea is also a notable source of caffeine) in the afternoon can still benefit our GM as they are rich in polyphenols too!

A spread of protein, vegetables and legumes and a slate plate with

5.Identify deficiencies

Certain nutrients such as iron and vitamin B12 play an important role in supporting energy levels and a deficiency in these can lead to anaemia, for which the most common symptoms are feeling tired and weak.

Iron and vitamin B12 are required to create red blood cells which are important for transporting oxygen around the body. People who eat a 100% plant-based diet i.e. vegan are at higher risk of developing anaemia because the main sources of iron and vitamin B12 are meats and animal products.

If you’re concerned chat to your GP or dietitian about whether you need a blood test which alongside a diet history can help to identify many common deficiencies that may be impacting your energy. At The Gut Health Clinic, we can help identify and build you personalised meal guidance to help prevent, manage and treat nutrient deficiencies – It’s worth noting that not all deficiencies can be measured by blood tests, take calcium for example.

6. Look after your microbes

Our GM is responsible for the breakdown and digestion of a lot of the food we eat and therefore plays an important role in the absorption of energy and nutrients from food.

A study published in the Journal New Microbes and New in 2021 found that symptoms of fatigue were correlated with the levels of specific species of gut bacteria. Other studies have also linked fatigue with gut dysbiosis which is where there is an imbalance of bacteria within our gut. Of course, these are correlations, and not causation but nonetheless it highlights the importance of us having a diverse microbiome- which interestingly can also produce a range of vitamins including b12.

We can optimise our GM by aiming for 30 plant points per week.

Illustration of a woman picking out a grain out of a tapestry of different types of plants to show plant diversity


It is important to accept that everyone has low energy from time-to-time but it’s empowering to know that there are plenty of simple ways we can combat it. Why not try implement a few of the above principles and see how they positively impact you – and be sure to let us know over at @theguthealthdoctor.


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