A Dietician's Guide To Avoiding An Afternoon Slump

By Rosemary Martin, BSc MSc RD

By Rosemary Martin, BSc MSc RD

You’ve probably been there: it’s mid-afternoon and your energy levels are rapidly diminishing. Perhaps you’ve noticed a reduction in focus, you’re feeling more tired, and irritable than you were earlier in the day, or you might just simply be  lacking  creativity. Commonly known as the ‘afternoon slump’,  this drop in energy and motivation often comes hand in hand with  a demanding craving for high-energy snacks or caffeinated drinks.

 Although these accounts are anecdotal, a growing body of evidence is clarifying the science behind this common problem. In other words, it’s now evident that we can take steps to prevent this unhelpful slump. What if our quick-fix attempts to recharge our battery are actually working against us? Can our food choices, both earlier in the day and at slump-time, really make a difference? It is always helpful to understand what’s going on inside your body when you’re looking to make changes, and there are a number of factors that can impact that all-too-familiar afternoon slump. By breaking these down, you’ll gain a deeper understanding of how to circumvent unwanted dips in energy. To help you get started, along the way I’ll be sharing my simple top tips to keep you feeling fired up all day.

What causes an afternoon slump?

Our bodies go through a natural cycle of fluctuating hormones and brain signals over the course of 24 hours (1). This cycle helps control when we feel awake and when we feel sleepy, and is referred to as our ‘circadian rhythm’. Along with sleepiness at night, I find it comforting to know that a drop in alertness in the middle of the afternoon is a normal part of this rhythm.

The good news is that although our circadian rhythm plays a central role in the afternoon slump, all is not lost. There are other factors, within our control, that impact it too. If you have struggled with poor-quality sleep in recent nights, or you are dealing with a stressful time in your life, you may find that your 3pm slump hits you just a little bit harder. But even if you sleep well and feel generally at ease, you may still struggle if you don’t address the role that nutrition plays in our energy levels. What and when we choose to eat can significantly improve or worsen our experience of an afternoon energy crash.

So, what can we do?

One of the first things to consider is what you have for breakfast and lunch. If you  frequently opt for meals that contain a large proportion of refined carbohydrates,  found in the likes of low-fibre cereals, white breads and pastries, the level of sugar in your bloodstream will rise rapidly. This spike in blood sugar will be shortly followed by a fast and significant drop. All carbohydrates that we eat break down into sugars in our digestive system, but in the case of more refined carbohydrates, such as white flour and table sugar, this happens much more quickly. This sudden increase in blood sugar  prompts a rapid release of a hormone called insulin.  Insulin is responsible for moving sugar out of our blood and into our cells,  so that our blood sugars drop back down. It is this  decline in blood sugar levels that can contribute to tiredness and fatigue in the afternoon, driving you to seek out more sugar to bring your blood sugar back into balance (2).

 Although rising and falling blood sugar levels  are a completely normal part of eating, we can temper those peaks and troughs by making some simple changes to our diet. Here are my five top tips to minimise the slump and fuel you through your day with a little more verve.

1. Swap refined carbohydrates for whole grain alternatives

Contrary to popular belief, you don’t have to completely cut out carbohydrates to manage your blood sugars. To help keep your blood sugar levels in check, it’s as simple as swapping white bread, pasta and rice for whole grain alternatives. Quinoa, buckwheat and barley are also excellent options.  Incorporating one of these as part of a balanced plate  will play a pivotal role in supporting and maintaining a healthy gut, due to the high fibre content of these whole grains. Eating to support your gut microbiome (the digestive system's bacterial ecosystem) can massively aid blood sugar stability and, in turn, help prevent sugar crashes (3).

2. Include a good source of protein and healthy fats

Alongside your portion of starchy carbohydrates, balance your meals with whole food sources of protein and fats. These will help to slow down the release of sugar into your blood and keep your energy levels steady in the hours afterwards, as well as ensure you get the nutrients you need. Healthy fats are found in foods such as avocado, nuts, and olive oil.  Including these on your plate will help you feel fuller for longer, as well as support the absorption of  nutrients such as vitamins A, D, E and K.

3. Up your fruit and vegetable intake

We all know we should be eating fruits and veggies, but especially so if you often suffer from an energy decline later in the day. This is because they’re packed with vitamins and minerals,  including B vitamins, vitamin C, iron and magnesium,  all of which help us to naturally produce energy (4). The trick to eating enough is filling half of your plate with colourful fruits and vegetables. This doesn’t mean completely overhauling the way you already eat, but making simple additions: for example, you could add berries to your breakfast, spinach and tomato to your sandwich, or roasted Mediterranean veggies to your dinner.

4. Don't skip meals

When life feels really busy, you might find yourself missing a meal without even realising - that is, until you feel yourself feeling tired, demotivated and craving sugar. Skipping meals also means missing out on the energy and nutrients that a healthy, balanced meal offers, which later drives you towards less healthy options as a quick fix. Aim to have regular meals at times that fit your schedule, and if you’re someone who tends to get hungry between meals,  make sure you have some nourishing snacks such as fruit, nuts, or veggie sticks and hummus stocked up on your desk or in your bag.

5. Stay hydrated with regular (non-caffeinated) drinks

Dehydration is a common cause of fatigue, lack of concentration and energy dips (5). In fact, being  as little as 2% dehydrated can impair your ability to carry out tasks (6). On busy days it can be hard to remember to drink, but a regular supply of fluid, such as water, herbal tea or decaffeinated drinks can help to keep you on form.Try keeping a water bottle on your desk as a visible reminder to keep sipping throughout the day, and stop you having to interrupt focus all the time to refill a small glass.

 As hard as it may be, try not to rely on caffeine to get you through your slump. Caffeine  remains active in your system for many hours after drinking it, which can  decrease the length and value of your deepest sleep that night and lead to lower energy levels the next day.

The take-home message

Just a few tweaks to your dietary choices can help you mitigate the afternoon slump. In summary:

1. Swap refined carbohydrates for whole grains

2. Balance meals with protein and healthy fats

3. Embrace a colourful array of fruits and vegetables

4. Avoid skipping meals

5. Stay hydrated

This holistic strategy not only  helps stabilise the ups and downs of your natural circadian rhythm but also promotes overall well-being by enjoying consistent energy levels. So, bid farewell to the afternoon slump and usher in a renewed sense of vigour and productivity throughout your day.

Rosemary Martin, BSc MSc RD




1. Valdez P. (2019). Circadian Rhythms in Attention. The Yale Journal Of Biology And Medicine, 92(1), 81–92.

2. Wyatt, P., Berry, S. E., Finlayson, G., O'Driscoll, R., Hadjigeorgiou, G., Drew, D. A., Khatib, H. A., Nguyen, L. H., Linenberg, I., Chan, A. T., Spector, T. D., Franks, P. W., Wolf, J., Blundell, J., & Valdes, A. M. (2021). Postprandial glycaemic dips predict appetite and energy intake in healthy individuals. Nature Metabolism, 3(4), 523–529.

3. Soare, A., Khazrai, Y. M., Fontana, L., Del Toro, R., Lazzaro, M. C., Di Rosa, C., Buldo, A., Fioriti, E., Maddaloni, E., Angeletti, S., Di Mauro, A., Gesuita, R., Skrami, E., Tuccinardi, D., Fallucca, S., Pianesi, M., & Pozzilli, P. (2017). Treatment of reactive hypoglycemia with the macrobiotic Ma-pi 2 diet as assessed by continuous glucose monitoring: The MAHYP randomized crossover trial. Metabolism: Clinical And Experimental, 69, 148–156.

4. Tardy, A. L., Pouteau, E., Marquez, D., Yilmaz, C., & Scholey, A. (2020). Vitamins and Minerals for Energy, Fatigue and Cognition: A Narrative Review of the Biochemical and Clinical Evidence. Nutrients, 12(1), 228.

5. Ganio, M. S., Armstrong, L. E., Casa, D. J., McDermott, B. P., Lee, E. C., Yamamoto, L. M., Marzano, S., Lopez, R. M., Jimenez, L., Le Bellego, L., Chevillotte, E., & Lieberman, H. R. (2011). Mild dehydration impairs cognitive performance and mood of men. The British Journal Of Nutrition, 106(10), 1535–1543.

6. Adan A. (2012). Cognitive performance and dehydration. Journal of the American College of Nutrition, 31(2), 71–78. https://doi.org/10.1080/07315724.2012.10720011.

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