Constipation: good and bad food

Plant-based foods are a good place to start. A diet rich in fresh fruit and vegetables provides lots of roughage and numerous other vitamins and minerals essential for a healthy body. Where possible, try them raw or steamed rather than boiled to keep them rich in other nutrients, although tinned and frozen are also fine for fiber intake. If they’ve got edible skin, leave it on, as often the skin is packed with fiber, vitamins, and minerals.

Green vegetables are a good choice in particular, like:

• broccoli
• spinach
• potatoes with the skin on
• carrots with the skin on

Fresh fruits high in fiber content include:

• apples with skin on
• raspberries and blackberries
• figs

Dried fruits are effective, such as:

• prunes
• dried apricots
• dates

Legumes (plant food that grows in pods) or pulses (dried-out legumes) such as:

• broad beans, garden peas, and runner beans
• lentils
• chickpeas
• kidney beans, black-eyed peas, and even baked beans

Nuts and seeds can also be a good source of fiber, such as:

• almonds
• peanuts
• sesame seeds
• sunflower seeds

It’s also a good idea to swap white foods for brown foods, as their whiteness indicates the bran and roughage have been stripped out in processing to make them more palatable and visually appealing. Examples include:

• whole meal or brown bread
• brown rice
• whole oats
• wholewheat pasta
• wholegrain cereals, instead of cornflakes or rice-based cereals
• wholegrains like buckwheat

Finally, you may see some processed foods with a label that says “fortified with fiber” - choose these over other options:

• certain breakfast cereals like Shredded Wheat or Muesli
• certain juices and smoothies - unsweetened and unprocessed are the healthiest options

Generally, you need about 30 g of fiber daily, but many of us fall short of that. Aim for a varied healthy diet, adding some of the fiber-rich foods to your normal meals and snacks, like a handful of berries on healthy breakfast cereal, and substituting certain foods for an option with more roughage.

The Dietary Guidelines for Americans suggests any food labels proclaiming 5 g of fiber per 100 g are "high in fiber” and those with 2 g or more are “a source of fiber.”

As a general guide, 30 g of fiber may be made up of the following options, with fiber per 100 g:

• shredded wholewheat or bran cereals contain 13-25 g
• two slices of wholemeal bread contain 7 g
• boiled broccoli contains nearly 3 g
• boiled parsnips contain 4.7 g
• figs contain nearly 7 g
• baked beans in tomato sauce contain nearly 7 g
• boiled green beans contain 4 g

You may see references to soluble and insoluble fiber. We need a mixture, but soluble fiber is found in oats, fruit, vegetables, beans, and pulses, and insoluble fiber is found in wholemeal bread and wholewheat cereals.

You may wish to reduce or leave out certain foods that can exacerbate constipation, particularly while you’re experiencing a bad episode. These include red meat, alcohol, and lots of caffeinated drinks like tea, coffee, and cola. Highly processed “white” foods, processed microwaveable or frozen meals, and fatty fast foods like chips and burgers are all ones to side-step.

It’s a myth that eggs and dairy products can cause constipation. They have lots of wholesome protein and nutrients, so they are good options for other aspects of your health, but they contain no fiber, so they won’t necessarily help constipation.

Bananas seem to have a constipation-promoting myth around them, but ripe bananas can be very helpful at shifting a blockage.

One exception to these rules is if you have IBS that tends towards constipation. You should keep a diary of foods and symptoms, and you may need specific dietary advice, especially to start a particular treatment diet called the FODMAP diet.

Those with gluten sensitivity may find cereals and wholegrains give them bloating and gas, so they may prefer sticking with fruit and vegetables to get their fiber. It's a personal choice.

Certain oils are known for facilitating the passage of food through the gut, such as olive oil and flax seed oil.

Some studies have shown that probiotics may help constipation, but the evidence is mixed so far. If you want to try this, go for live yogurt or other foods or supplements that contain Bifidobacterium lactis – give it at least 4 weeks to see if it’s helping. At the very least, it will help you on the way to a healthy gut by cultivating good microbiome bacteria, which isn’t known to be harmful.