Healthy people swapped from African diet to Western one and it had shocking effect after just two weeks

We've all heard the phrase 'you are what you eat', but what exactly happens to your body when you completely change from one diet to another?

A group of researchers from Radboud University and KCMC University in Tanzania have tested just that, getting Tanzanian men to swap their plant-based, fibre-rich African diets for a processed, calorie-dense Western one.

The 77 participants in the study - all healthy young men from rural and urban Tanzania - were instructed to switch from their traditional Kilimanjaro diets to one made up of processed foods like fried chicken, pizza and crisps.

And the effects on their health after following the Western regimen were shocking.

Participants in a study saw alarming effects on their body after switching from their African diet to a processed Western one (Jonathan Knowles/Getty)

In just two weeks, the men gained an average of 5.7 pounds.

On top of this, researchers found a steep increase in inflammatory markers in their blood. There were also signs that their immune systems had weakened as well as metabolic changes associated with the development of heart disease and diabetes.

But these changes didn't stop when the men returned to their healthier diets.

Some of the negative effects of the processed foods lingered for up to four weeks after they stopped eating them, with study authors noting how short-term changes can have longer term impacts.

The researchers also tested the reverse scenario, instructing a group of men who typically eat a Western diet to follow a regimen of primarily fruits, vegetables, legumes, brown rice and whole grains.

Researchers say the study highlights the benefits of a plant-based African diet on the body (Maria Korneeva/Getty)

They observed the opposite effects to the other group with these participants experiencing a reduction in both inflammation, which has been linked to a whole host of illnesses including Alzheimer's disease and arthritis, and proteins in the blood associated with a number of conditions including heart attacks and strokes.

Reverse metabolic changes to those on the Western regimen were also noted.

Dr. Quirijn de Mast, an internist and infectious disease specialist at Radboud University and one of the study's authors, said: "Previous research has focused on other traditional diets, such as the Japanese or Mediterranean diet... but African heritage diets hold untapped potential for promoting health.

"The African diet includes plenty of vegetables, fruits, beans, whole grains and fermented foods.

"These diets are diverse, rich in fibre and feature unique food products that may offer specific health advantages," he continued.

"Our study highlights the benefits of these traditional food products for inflammation and metabolic processes in the body.

"At the same time, we show how harmful an unhealthy Western diet can be."