It is easy to reach for packaged snacks, instant noodles or sugary drinks in a busy city life. They are convenient, fast, and everywhere.
However, as more Kenyans fill their pantries with ultra-processed foods, nutritionists and gastroenterologists are raising alarm about the impact on our digestive health.
“Unprocessed foods are foods that don’t contain artificial additives or preservatives,” says Kepha Nyanumba, a consultant nutritionist.
“They are rich in fiber, which helps clean the digestive tract, supports regular bowel movements, and promotes the growth of beneficial bacteria that reduce inflammation. Compared to ultra-processed foods, whole foods help good microbes thrive and enhance nutrient absorption.”
The gut microbiome, a complex ecosystem of bacteria, fungi and other microbes, plays a central role in digestion, immunity, and even mood regulation. A diet dominated by ultra-processed foods can upset this balance, leading to bloating, constipation and more serious metabolic disorders.
Dr Alemanji Ajua, consultant gastroenterologist at Aga Khan Hospital, explains: “Ultra-processed foods have been shown to harm the microbiome.
You see altered bowel habits, bloating, and sometimes irritable bowel syndrome. Diets rich in minimally processed foods, such as nuts, fruits, vegetables, and olive oil, support gut health and overall well-being. It’s not just about digestion, the effects ripple across your entire system.”
But what exactly makes whole foods so effective for the gut?
Joy Ouma, a registered dietitian and pediatric nutritionist at Aga Khan University Hospital, breaks it down: “Whole foods contain natural fibers and antioxidants like vitamins A and E. They also provide omega-3 fatty acids from nuts and seeds, vitamin K from fermented foods, and polyphenols from colorful vegetables and fruits. All these nutrients feed the gut bacteria, keep the colon healthy, and prevent metabolic disorders.”
Ms Ouma adds that the problem with highly processed foods is not only what they lack but what they contain.
“Added sugars, salts and chemical preservatives in processed foods can disrupt the gut lining. Over time, this leads to bloating, constipation, poor absorption of vitamins and sometimes even sleep disturbances.”
Among the foods most beneficial for gut health are leafy vegetables like spinach, cabbages and traditional greens; fruits such as bananas, apples, pears and watermelon; legumes and whole grains including beans, lentils and whole brown bread.
Other are fermented foods like mala and natural yogurt; and nuts and seeds like almonds, flax, and macadamia nuts. Traditional herbs and spices such as ginger and turmeric also provide antioxidants and anti-inflammatory compounds that protect gut health.
Both Mr Nyanumba and Ms Ouma highlight the importance of traditional diets.
“Indigenous foods are naturally rich in fiber, vitamins, and minerals, and they don’t contain refined oils, sugars, or additives,” says Ms Ouma.
Fast food delivery menu background with various burgers, cheeseburger, nuggets, french fries, fizzy soda drinks.
Photo credit: Shutterstock
“Incorporating these foods helps sustain gut health in a way that highly processed foods never can.”
Switching to minimally processed foods is not just about avoiding disease, it’s about improving digestion and overall quality of life.
Mr Nyanumba notes: “Fiber from whole foods adds bulk to stool, prevents constipation and promotes a healthy gut lining. Prebiotic fibers in onions, garlic, bananas, beans and lentils feed beneficial bacteria, while resistant starch in potatoes, plantains, legumes and whole grains nourishes the gut lining and supports nutrient absorption.”
Ultra-processed foods, by contrast, slow digestion, reduce nutrient absorption, and can exacerbate conditions such as acidity, acid reflux, gastritis, and irritable bowel syndrome.
“When the gut is not functioning well, you may notice bloating, fatigue, or even micronutrient deficiencies,” says Ms Ouma.
“Over time, these issues can contribute to metabolic disorders and a range of other health problems.”
For those juggling work, family and other commitments, Ms Ouma emphasises that healthy eating is possible with planning.
“Meal prep is key. Boil beans in advance, store yogurt in the fridge, steam or grill vegetables. Even with a busy schedule, small, consistent changes like including vegetables at lunch and dinner, adding fruits as snacks, and reducing sugary processed foods can have a big impact over time.”
Both experts caution against relying on supplements as a replacement for real food.
“Supplements can support your diet, but they cannot replace the nutrients you get from whole foods,” says Ms Ouma.
“Focus first on eating a variety of minimally processed foods before considering supplements.”
The message is clear: shifting from ultra-processed to unprocessed or minimally processed foods can reverse digestive issues, improve nutrient absorption, and enhance overall health. While convenience may tempt many into the fast-food aisle, the benefits of traditional, whole, and fiber-rich foods for the gut are undeniable.
“Healthy digestion starts with the food we eat,” says Nyanumba. “It’s a choice that supports our gut, our metabolism, and ultimately, our long-term well-being.”
