Kenyans gain 11kg after moving to US – research

It all begins with a burger here, a soda there and less walking, and before they know it, many migrants become part of statistics that show over half (54 per cent) of African immigrants in the US are obese.

Researchers interviewed African immigrants in the US, including Kenyans, Nigerians and Ghanaians.

They were asked about their weight before and after moving to the US. At least eight in 10 gained about 11 kilogrammes in the first few years, with most of the increase linked to increased fast-food consumption, reduced physical activity, and longer hours spent sitting at work.

The findings, published last month in the Journal of Racial and Ethnic Health Disparities, warn that health risks can quickly rise when more sedentary, high-calorie environments replace traditional lifestyles.

“The majority of participants said their diets had changed since migration to the US, specifically, consuming more fast food and sweets and less fruit and vegetables,” said the researchers, who include Jane Kimani of UHAI for Health Inc, an NGO she founded to empower African immigrants with strong ties to Kenya.

 “The most common barriers to a healthy diet reported were fruit and vegetables not tasting as good as they did in their home African country, fruit and vegetables spoiling quickly and difficulty in finding traditional African fruit and vegetables.”

The paper is titled, 'An Examination of African Immigrants With Overweight or Obesity: Weight, Lifestyle Behaviours, and Body Image Following Immigration'.

The United States Census Bureau's American Community Survey (ACS), which collects data on ancestry, in 2022 said there were about 122,131 people who identified their ancestry as Kenyan in the US.

Physical activity also drops sharply, and many migrants no longer ‘hustle’ on foot as they did back in Kenya.

They reported that their jobs in the US involved sitting for long hours, compared to more physically active routines in Kenya. Only about four in 10 met the recommended levels of exercise.

“About 38.10 per cent of participants met the Physical Activity Guidelines, and the most common barriers to physical activity were feeling too tired and being too busy. Most (87 per cent) participants desired leaner body types,” the researchers said.

The findings mirror a broader trend seen among immigrant populations globally, where moving into high-income countries often brings access to more food, but also more processed, calorie-dense diets and less daily movement.

But for Kenya, the study’s implications go far beyond migration.

Health experts said the same conditions driving weight gain abroad are now emerging locally, especially in urban areas like Nairobi, Mombasa and Kisumu, where fast food chains are expanding rapidly, processed foods are becoming cheaper and more available, and lifestyles are increasingly sedentary.

Traditional Kenyan diets are rich in whole grains, vegetables and home-cooked meals.

Physical activity is also built into daily life through walking, farming and manual work. But that is changing fast, especially among younger, urban populations.

“Results also found that more recent African immigrants were more likely to have unhealthy BMI after migration than those who migrated earlier,” Kimani’s team said.

"This may be partly explained by the recent infiltration of Western diets and sedentary lifestyles in Africa, particularly in urban areas.” 

“Future research is needed to investigate how diet and physical activity have changed in Africa in recent years.”

The researchers noted one limitation is that they required their participants to have lived in the US for at least three years, but they could not be sure that three years is enough time for immigrants to adopt American diet and physical activity habits.