Overnight oats with kiwi: a gentle, fiber-rich breakfast

This is a breakfast you make the night before, in about five minutes, with nothing more than a jar and a spoon. By morning it's ready to eat cold straight from the fridge, or warmed up if you prefer.

It also pairs two foods with real research behind them: oats, a well-known source of the soluble fiber beta-glucan, and green kiwifruit, which has been tested head to head against a fiber supplement for constipation.

Why these two ingredients

Oats. Oat beta-glucan is the soluble fiber behind oats' reputation for heart health. A meta-analysis of 28 randomized trials found that eating at least 3 grams of oat beta-glucan a day lowered LDL cholesterol by 0.25 mmol/L, about 10 mg/dL, and total cholesterol by 0.30 mmol/L compared with control diets, without changing HDL cholesterol or triglycerides (Whitehead et al., 2014). How much beta-glucan a bowl provides depends on the product and portion, so think of this breakfast as one helpful part of your day, not a cholesterol treatment.

Green kiwifruit. In an international randomized trial, 184 people, including healthy volunteers and people with functional constipation or IBS with constipation, ate either 2 green kiwifruits or 7.5 grams of psyllium a day for four weeks, then switched after a break. Kiwifruit increased complete spontaneous bowel movements by 1.53 a week in people with functional constipation and by 1.73 a week in people with IBS with constipation. It also improved measures of digestive comfort, and no significant adverse events were seen (Gearry et al., 2023).

Ingredients

Makes 1 jar.

• 1/2 cup old-fashioned rolled oats
• 1/2 cup milk, lactose-free milk or unsweetened soy milk
• 1/4 cup plain yogurt, regular or Greek (lactose-free or plant-based if you prefer)
• 1 teaspoon chia seeds (optional)
• 1/4 teaspoon ground cinnamon
• 1 teaspoon maple syrup (optional)
• 2 ripe green kiwifruit
• 1 tablespoon chopped walnuts or pumpkin seeds

Steps

1. Add the oats, milk, yogurt, chia seeds, cinnamon and maple syrup to a jar or container with a lid.
2. Stir well, making sure no dry oats are stuck at the bottom.
3. Cover and refrigerate overnight, or for at least 6 hours.
4. In the morning, peel and dice the kiwifruit. Short on time? Halve them and scoop out the flesh with a spoon.
5. Stir the oats, adding a splash of milk if they're too thick. Top with the kiwifruit and the nuts or seeds.
6. Eat cold, or microwave the oat base for about 60 seconds, stirring halfway, before adding the fruit.

The oat base keeps in the fridge for up to two days, so you can make two jars at once. Add the kiwifruit fresh each morning.

Swaps and variations

• No kiwifruit on hand? Top with berries or a sliced orange instead. You'll lose the kiwifruit-specific research, but it's still a fiber-rich breakfast.
• Prefer it warm? Simmer the oats and milk on the stove for about 5 minutes, stir in the yogurt off the heat, and add the toppings.
• Want more protein? Use Greek yogurt, or stir in a tablespoon of peanut or almond butter.
• Dairy-free? Use unsweetened soy milk and a plant-based yogurt.
• Different crunch? Swap the walnuts for toasted sunflower seeds or a few chopped pecans.

Make it gentler on a sensitive gut

• Build up slowly. If you don't usually eat oats, start with 1/4 cup oats and one kiwifruit, and leave out the chia seeds for the first week.
• Choose lactose-free dairy if regular milk or yogurt tends to bother you.
• Skip sugar-free syrups made with sugar alcohols. Sugar alcohols belong to a group of carbohydrates that aren't fully absorbed and are fermented in the colon. Especially at higher intakes, they can cause abdominal discomfort, gas and diarrhea (Grabitske and Slavin, 2009).
• Leave out "prebiotic" boosters. Many are based on inulin or chicory root. Here's why those can backfire.

A note on oats and celiac disease

People with celiac disease avoid wheat, rye and barley, and whether oats belong on a gluten-free diet has been debated. A systematic review of 28 studies found no evidence that adding oats to a gluten-free diet affected symptoms, intestinal biopsies or blood tests in people with celiac disease. However, all of the randomized trials used pure, uncontaminated oats, and the overall quality of evidence was low (Pinto-Sánchez et al., 2017).

If you have celiac disease, choose oats labeled gluten-free and talk with your gastroenterologist or dietitian before adding them.

When to check in with a doctor

Food changes like this one can help with constipation. See your doctor if constipation is new and lasts more than a few weeks, or if you notice blood in your stool, unexplained weight loss, anemia or severe abdominal pain.

Sources

1. Whitehead A, Beck EJ, Tosh S, Wolever TM. Cholesterol-lowering effects of oat β-glucan: a meta-analysis of randomized controlled trials. Am J Clin Nutr. 2014;100(6):1413-21. PMID 25411276
2. Gearry R, Fukudo S, Barbara G, et al. Consumption of 2 green kiwifruits daily improves constipation and abdominal comfort: results of an international multicenter randomized controlled trial. Am J Gastroenterol. 2023;118(6):1058-1068. PMID 36537785
3. Grabitske HA, Slavin JL. Gastrointestinal effects of low-digestible carbohydrates. Crit Rev Food Sci Nutr. 2009;49(4):327-60. PMID 19234944
4. Pinto-Sánchez MI, Causada-Calo N, Bercik P, et al. Safety of adding oats to a gluten-free diet for patients with celiac disease: systematic review and meta-analysis of clinical and observational studies. Gastroenterology. 2017;153(2):395-409.e3. PMID 28431885

This article is for general information and isn't medical advice. If you have celiac disease, a food allergy or a digestive condition, check with your healthcare provider or dietitian before changing your diet.