How to stop feeling tired after eating

Key Points

• Eating smaller meals may help reduce tiredness after eating
• Opt for low-GI and low-GL meals
• Reduce consumption of refined carbohydrates

A big bowl of pasta, a spicy burrito or a juicy burger. Who hasn’t indulged in these types of foods and collapsed on the couch in a food coma afterwards? According to Accredited Practising Dietitian Kate Agnew, there are a few reasons why you might feel tired after eating certain foods.

Here’s the deal: it’s not just about what you eat – it’s about how much and how often. Read on if you’re curious about why you may feel sick and tired after eating.

How to stop feeling tired after eating

If you find yourself feeling tired or even falling asleep after eating, Kate advises eating smaller meals throughout the day rather than three big meals, as larger meals may result in an insulin spike followed by a drop in blood glucose, which can lead to tiredness. (More on that later.)

Not sure how to cut down the size of your meals without sacrificing the things you enjoy? Try Kate’s plate balancing hack.

“When you look at your plate, make sure half is non-starchy vegetables, like carrot or cucumber, not starchy vegetables like potato and corn.

“A quarter of your plate should be a lean protein source, and the last quarter should be a carbohydrate source. If you want starchy vegetables, they should come into the quarter portion of carbohydrates. And to add a bit of healthy fat, you can add avocado or olive oil.”

So the key is to make sure half your meal contains non-starchy vegetables like:

• asparagus
• broccoli
• cabbage
• carrots
• cauliflower
• celery
• cucumber
• eggplant
• salad greens
• snow peas
• sprouts
• zucchini

And keep your stomach happy and satisfied with nutritious and filling snacks between your three square meals a day. 

“Try eating small portion sizes for your main meals, with snacks like a handful of nuts or fruit in between,” Kate tips.

Why do we feel tired after eating?

Not sure what insulin has to do with fatigue after eating? Let’s look at the miraculous digestion process.

Digestion breaks down carbohydrates, protein and fat into glucose, amino acids and fatty acids, causing blood glucose levels to rise. Insulin is then released by the pancreas to move glucose from the blood to cells, causing blood sugar to drop. 

This up-and-down cycle can make you feel tired. 

Additionally, tryptophan, an essential amino acid found in foods like milk, cheese and turkey, may also contribute to sleepiness. Insulin can help tryptophan pass through the blood-brain barrier, leading to the production of serotonin and melatonin, which promote relaxation and sleep.

Eating a Paleo diet won’t necessarily help you to stop feeling tired after eating

Does intermittent fasting or Paleo minimise tiredness?

Some research shows intermittent fasting may help reduce tiredness and fatigue for some individuals. Your body’s response to fasting is that your tissues become more sensitive to insulin, allowing your cells to use blood glucose more effectively.

Regarding Paleo, there’s no evidence to show that skipping grains will reduce tiredness after eating. The ‘Paleolithic diet’ favours meat, vegetables and fruit over grains and dairy. However, Kate says it’s a myth that avoiding grains is necessary for health, with a wealth of research pointing to the positive effects whole grains have on gut bacteria.

“Whole grains are an important source of fibre and are one of the key elements needed to produce short-chain fatty acids,” says Kate. “If you cut out grains and try to get all your fibre from vegetables, you will likely miss out on other important fibre types. So the message is to consume good-quality wholegrains.”

Fried food might taste great, but it leaves some people feeling tired and sluggish after eating

Foods that make you tired and sluggish

We’ve already established that your insulin spikes when you eat larger meals, but what about carbs and protein? When we consider the foods that will make us feel tired and sluggish, we need to take into account the glycaemic index (GI) as well as the glycemic load (GL).

The GI ranks carbohydrates on a scale from 0 to 100 in terms of how quickly and how much they raise our blood sugar levels. While the GL takes into account both the GI (how quickly the food raises blood sugar) and the amount of carbohydrates in a portion.

Let’s apply this food science to a national favourite – pasta. A standard white pasta has a low GI of 43. And that’s a good thing. According to the Australian dietary guidelines, one serve of pasta is about half a cup (75–120g). If we look at a 90g serve of white pasta boiled to al dente texture, its GI is 43 and its GL is 9.5g. So while the GI remains the same, the GL is lower due to the portion size. Therefore, a huge plate of spaghetti might cause your blood glucose levels to spike faster than a small serving, which may leave you feeling sleepy afterwards.

So it’s not just the glycaemic index of the food that matters; it’s also the amount you eat. “In terms of glycaemic load,” explains Kate, “a tiny piece of cake doesn’t spike your insulin as much as a huge piece.”

And if you’re thinking about what foods make you sleepy, consider how often you like to add wine to your dine. Alcohol is a depressant and slows down the central nervous system, so it could be another culprit that may make you feel tired and sluggish.

The number 1 trick to help you avoid feeling tired after eating

“The best thing to avoid feeling tired after eating is to have a well-balanced, low-glycaemic-index, low-glycaemic-load meal,” says Kate.

You can achieve that with the plate trick we discussed earlier – getting the right balance of foods on your plate – as well as eating smaller meals to help you avoid sleepiness after eating.

What foods give you energy?

While all foods contain calories and therefore give you energy, the foods that are more likely to provide you with sustained energy without leaving you feeling tired are:

• vegetables
• fruit
• iron-rich foods, like red meat, eggs and leafy greens
• wholegrain or pulse pasta
• legumes, like chickpeas and lentils
• rolled oats

Whether you eat three main meals or graze throughout the day, check how tired you feel afterwards and consider making adjustments

The key takeaway: it’s not one size fits all

Some people find they have more energy if they graze throughout the day, whereas others prefer three solid meals. It’s about paying attention to your body and making tweaks as needed.

“And don’t forget the basics like drinking enough water throughout the day, getting enough sleep, exercising and minimising caffeine intake,” says Kate.

Of course, there may be other reasons for feeling tired, such as iron deficiency or other health conditions. If you think something more serious could be at play, visit a healthcare professional.

Related:

• Bread is back on the menu, so let’s make it work for you
• How to stop eating junk food – we have the secret!
• Is sugar really that bad for us?

Kate Agnew is an Accredited Practising Dietitian who is passionate about innovation and problem-solving in health & nutrition. Her goal is to ultimately create a healthier environment for all Australians.

Reviewed by healthylife health experts May 2023.