By Adam Mynott
BBC News, Naivasha
Many people are unaware that they have diabetes
It is called the "silent killer".
In Kenya the official rate for people suffering from diabetes is 3.5%, but even the experts at the Ministry of Health in Nairobi know this is a ludicrous underestimate.
The real rate of diabetes in Kenya is more like 10%, and some say it could be higher.
Of all the serious non-communicable diseases, diabetes has the distinction of being the least diagnosed.
The World Diabetes Foundation, which is issuing grave warnings that diabetes is turning into a pandemic, estimates that in the developing world a quarter of people who have diabetes don't realise it.
The symptoms of thirst, aching joints, failing eyesight and loss of balance are put down to old age or a persistent cold or a virus.
It is also a disease that preys on people who are relatively affluent, so in the developing world, where the increase is most dramatic, it is catching many by surprise.
Naivasha town sits alongside the eponymous lake in the Rift Valley about an hour's drive from Kenya's capital, Nairobi.
It is a scruffy conurbation that doesn't, at first sight, betray relative affluence.
A third of the cut flowers sold in Europe are grown in greenhouses clustered around the southern margin of Lake Naivasha and, while it hasn't made the town wealthy, the flower business has provided thousands of jobs and injected money into Naivasha.
It is this money that is indirectly pushing up the rate of diabetes locally.
The town's District Hospital held an open day recently and the 700 or so people who dropped in were tested for diabetes.
These weren't people who were ill. They were just visitors, but doctors found that more than 5% of them had diabetes.
Dr Osborn Tembu, who runs a clinic for diabetes sufferers every Thursday, was not surprised.
He said "Most people don't visit the hospital until the symptoms get quite severe. For months people can be walking around with elevated sugar levels, which can be very harmful."
He said the other problem in diagnosing diabetes is that, "the vast majority of people in the villages don't know about diabetes. They are aware of the infectious diseases but diabetes, no."
Recently retired Naivasha businessman Amos Kit Kiranje knew about diabetes, but it was a while before he realised that something was wrong.
"I had thirst," he said, "excessive thirst, a lot or urination, blurred vision. I was actually seeing double. I suffered from, palpitations. I could not talk properly and in the mornings, I got up and immediately felt dizzy."
Mr Kiranje and at least 85% of people suffering from diabetes have Type II which is linked directly to a poor diet and a lack of exercise.
Type II diabetes is linked directly to a poor diet and a lack of exercise
By his own admission, Amos is carrying a bit too much weight and now he's retired, he's not as active as he used to be, like many others in Naivasha.
At the clinic at Naivasha District Hospital every Thursday he is told to cut down on starchy foods, to avoid sugary drinks and to take more exercise.
"I know now how to control my diabetes," he said, "but it's not easy."
Type II diabetes is hitting the developing world.
It is being contracted in places which are more used to hunger, malnutrition and poverty.
Type II diabetes is a disease of affluence and in communities in Kenya and the whole of the developing world its effects are increasingly severe because there is no natural resistance to it.
In the West, where diabetes is also a bad problem, there is a level of tolerance to it, which mitigates its prevalence.
In Africa, India, parts of the Far East and South America there is not.
Dr William Maina, the head of the non-communicable diseases unit at Kenya's Ministry of Health, is worried about changing lifestyles.
"Today we are seeing more people consuming unhealthy foods; foods that are high in carbohydrates, high in sugars, high in salts, high in fats. At the same time we are seeing people lead more sedentary lifestyles. This is exposing them to risks," he said,
"Diabetes is very serious. It's a killer."
Diabetes is already responsible for as many deaths as HIV/Aids, around 3m worldwide every year, but it gets nothing like the attention and publicity.
Kenya is launching a public health drive to inform and warn about diabetes.
Drinking milk helps ward off a condition linked to diabetes
While exercise and the right food can avert diabetes, restoring the correct sugar concentration in the blood in some patients, can only be achieved with prescribed insulin.
This is the other critical issue in the developing world.
Insulin is an expensive drug and in Kenya where the per capita income is put at $1,200 a year it is beyond the reach of many.
Amos Kiranje says it's a struggle for him to meet the costs, and compared to many he is not poor.
"I have to buy drugs for blood pressure as well and other things so I spend around 2,000 or 2,500 shillings ($38) every month.
"It's a lot of money."