Digestion is the single most common reason people come to see me, and also the area where I most often say the words “that needs a doctor, not a nutritionist”.
What actually happens
Digestion starts before food reaches your mouth — the smell and sight of a meal begins the process. Chewing breaks food down mechanically and starts carbohydrate digestion. The stomach adds acid and enzymes and holds food while it's broken down further. The small intestine does the great majority of the absorption. The large intestine reclaims water and hosts the bacterial population that ferments what you couldn't digest yourself.
The whole run takes somewhere between one and three days for most people.
The unglamorous things that help most
Eat more slowly
The most common thing I change, and the least popular. Chewing properly does real mechanical work that your stomach otherwise has to do, and the satiety signals that tell you you've had enough take about twenty minutes to arrive. Eating in eight minutes standing at the counter defeats both.
Eat sitting down, not doing something else
Digestion runs best when your nervous system isn't in a hurry. This isn't mysticism — it's the difference between the rest-and-digest and fight-or-flight states, and it has measurable effects on stomach emptying.
Fibre, built up slowly
Most Canadians get roughly half the fibre generally recommended. But adding twenty grams tomorrow will make you extremely uncomfortable and you'll conclude fibre doesn't agree with you. Add about five grams a week and drink more water alongside. More on fibre here.
Regular meal timing
Your gut has its own rhythm and prefers some predictability. Constant grazing means the migrating motor complex — the sweeping motion that clears the small intestine between meals — never gets to run.
Move after eating
Ten minutes of gentle walking helps gastric emptying and blood sugar both.
On elimination diets
Cutting foods out is the most common self-directed approach to digestive symptoms, and it's the one I'm most cautious about. Diets get narrower over time, the restriction itself reduces the diversity your gut bacteria depend on, and a genuinely restrictive protocol needs a defined endpoint and supervision.
If you've been cutting foods for months and still feel unwell, the answer probably isn't cutting more.
Some things belong with a physician and shouldn't be worked around with diet. Please make an appointment for any of these: blood in your stool, unexplained weight loss, difficulty swallowing, persistent vomiting, a lasting change in your bowel habits, severe or worsening pain, waking at night with symptoms, anaemia, or a family history of bowel cancer or inflammatory bowel disease. Coeliac disease also has to be tested for while you are still eating gluten — cutting it out first makes the test unreliable, so get tested before you change anything.
Where I do fit
Once anything serious has been ruled out, there's a great deal that eating patterns can help with: how much fibre and what kind, meal timing and pace, hydration, fermented foods, and working out which specific things are genuinely a problem for you rather than cutting broadly and hoping. That's the work.
This is general nutrition education, not medical advice, and it isn't intended to diagnose, treat, cure or prevent any condition. If you're pregnant or breastfeeding, taking medication, or managing a diagnosed condition, talk to your doctor or pharmacist before making changes.
Written by Mellissa Wallace, Registered Holistic Nutritionist, Okanagan BC.
More in Food & Health
- Why your energy crashes at 3pmBlood sugar in plain language, and the small changes to breakfast and lunch that flatten out the afternoon without more caffeine.8 min
- The nutrition side of sleeping betterCaffeine timing, alcohol, eating too late or too little, and the evening habits that quietly decide how the night goes.7 min
- How nutrition needs shift through the decadesIron in your twenties and thirties, the perimenopausal years, protein and bone health later on — what actually changes, and what stays the same.8 min