Why brain exhaustion leads to unhealthy snacking

Published Nov 1, 2024

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As we approach the end of the year, mental fatigue and burnout slowly start creeping in for many of us. Whether you're juggling work deadlines, family commitments, or personal goals, the mental load can feel overwhelming.

But did you know that exhausting your brain could actually make unhealthy snacks more tempting?

Recent research published in Neuroscience News revealed that mental fatigue intensifies the desire for rewards like unhealthy snacks. Both rats and humans who exerted cognitive effort sought out more rewards.

In the case of rats, they self-administered more cocaine, while humans rated snacks such as chips as tastier after engaging in mentally draining tasks.

Why mental fatigue increases snack cravings

This holiday season, avoid the trap of mindless snacking! Picture: Darina Belonogova/pexels

The study, led by Marcello Solinas and colleagues, suggests that this isn’t just about weakening willpower. Rather, cognitive fatigue seems to amplify how rewarding or pleasurable certain stimuli feel.

So, after a hard day of mentally taxing work, that bag of chips or chocolate bar doesn’t just look appetising, it may actually taste better to you.

In one experiment, participants were asked to perform a challenging mental task, suppressing thoughts of a white bear while listing other thoughts.

Afterwards, they were offered potato chips and rated them as better-tasting compared to those who hadn’t completed the task. In short, exerting mental effort didn’t just make people snack more, it made them enjoy the snacks more, too.

The researchers ruled out the possibility that this heightened reward response was a general effect of mental effort.

When participants completed difficult or easy writing tasks, only their ratings of chocolate increased, while judgments of less rewarding items like the length of a pen or the brightness of a yellow Post-it note didn’t change.

This research is a wake-up call, especially during the holiday season when stress tends to peak, and tempting snacks are everywhere.

The study highlights how mental exhaustion can make the brain more susceptible to rewards, leading us to crave and enjoy unhealthy foods more than usual.

For anyone trying to manage their weight, improve their diet, or even maintain steady energy levels throughout the day, this is an important finding.

It suggests that being mentally fatigued could make it harder to stick to your healthy eating goals, not because of weak willpower but because your brain is wired to seek out these highly rewarding foods when you’re tired.

Smart snacking solutions to combat mental fatigue:

Protein helps regulate hunger and keeps you fuller longer. Picture: Jonathan Borba/pexels

Choose protein-rich snacks

Protein helps regulate hunger and keeps you fuller longer. It also provides steady energy, which can help combat the dips in motivation that come with mental fatigue. Some great options include:

  • Greek yoghurt with berries
  • Hard-boiled eggs
  • A handful of almonds or walnuts

Choose fibre-packed foods

Fibre-rich snacks can help stabilise blood sugar levels and curb cravings for sugary or fatty treats. Try incorporating:

  • Carrot sticks with hummus
  • Apple slices with almond butter
  • Air-popped popcorn

Hydrate first

Often, what we interpret as hunger or cravings is actually dehydration. Before reaching for a snack, drink a glass of water or herbal tea. If you're still hungry after 10 minutes, choose a healthy snack.

Plan your snacks ahead

When you know you have a mentally taxing day ahead, plan your snacks in advance. Pre-portion healthy options like trail mix, veggies, or fruit so that when cravings strike, you have something nutritious ready to go.

Practise mindful eating

Mental fatigue can lead to mindless eating, where you reach for snacks without really thinking about it. Slow down and savour your food.