Have you ever wondered why some meals leave you feeling light and energised, while others leave you feeling bloated, sluggish or uncomfortable?
One explanation is that different foods digest at different rates, so combining foods with very different digestion times can interfere with digestion.
Our digestive systems are remarkably adaptable, and they are designed to digest mixed meals containing carbohydrates, proteins and fats, but the composition of a meal can influence how quickly our stomach empties, how nutrients are released and absorbed, and how comfortable we feel afterwards.
There isn’t one fixed digestion time for each food.
Fruit can digest within 20 to 30 minutes, carbohydrates typically take about 2 hours, whereas meat can take 4-6 hours, or even longer in some people to digest. But we are all different and so these times are just guidelines.
Digestion involves several stages.
It starts in the mouth, then moves through the stomach, small intestine and large intestine.
Starting in the mouth:
Digestion starts in the mouth. Chewing breaks food down mechanically and mixes it with saliva. Amylase is an enzyme in the saliva that starts the digestion of carbohydrates.
Moving to our stomachs:
Then the food moves to our stomachs where it is mixed with acid and digestive enzymes. Protein digestion begins here, and the stomach gradually releases its contents into the small intestine.
Small intestine:
The small intestine is where most of our digestion and nutrient absorption takes place. Enzymes from the pancreas and bile from the liver help break down carbohydrates, proteins and fats.
Large intestine:
Lastly, in the large intestine, water is absorbed and gut bacteria ferment some of the material that wasn’t digested earlier, particularly certain fibres and resistant carbohydrates and they are excreted.
Several factors affect the rate at which food moves through the digestive system
Many easily digested carbohydrates can be broken down relatively quickly, particularly when they are refined or highly processed. Whole grains, legumes and many vegetables contain fibre and resistant starch, which slow digestion and can be fermented by our gut bacteria.
Protein generally requires more digestive processing. The stomach’s acid and enzymes begin breaking proteins into smaller peptides, and further digestion takes place in the small intestine.
Fats tend to slow gastric emptying, which is one of the reasons why a meal containing a significant amount of fat can keep us feeling full for longer.
Fibre can slow the absorption of nutrients and influence intestinal transit. Some fibres also provide food for our gut microbiome.
So, does food combining matter?
The idea behind food combining is that certain foods should be eaten together while others should be separated. For this reason, it is often recommended that we should eat our fruits separately from our proteins and we should avoid combining carbohydrates and proteins.
For some people certain food combinations can affect how they feel. But the quantity we consume and how our food is prepared can also influence our digestion and any digestive symptoms we may experience.
Combining proteins and fats has become a very popular way of eating, especially with some of the ketogenic eating plans.
A meal high in both protein and fat can take longer to leave the stomach which can make us feel fuller for longer and can help prevent cravings and unwanted snacking. Some people though, have difficulty breaking down fats so consuming a high-fat meals can cause them to experience heaviness, reflux or discomfort.
Combining carbohydrates with fibre can slow our digestion and absorption.
The fibre in complex carbohydrates slows the release of glucose into our bloodstream and because of this we can manage our blood sugar levels better.
Fruit is one of the foods that does digest at a faster rate.
When we consume fruit after a large meal it can cause fermentation which could lead to bloating and discomfort in some people.
There are many factors that play a role.
These include the health and bacterial composition of our gut microbiome, digestive enzyme production, bile production, how much gastric acid is available, fibre intake, meal size, stress, how quickly we eat, whether we have chewed enough, and our individual food sensitivities.
Stress can also influence our digestive function.
Our digestion is strongly influenced by the parasympathetic nervous system which is the part of the autonomic nervous system associated with rest and digestion.
When we eat while stressed, rushed or distracted, digestion can be more difficult.
This is why something as simple as slowing down and relaxing before eating can be valuable. Every time we eat, we should, pause, breathe, smell our food, chew thoroughly and eat slowly. Digestion begins before our food even reaches our stomachs.
Listen to my interview with Anton Brink from Radio Cape Pulpit on 13 August 2026 to learn more. Listen to my next interview on Thursday at 7.45am.