One hundred thousand Kiwis are walking around with a chronic health condition without knowing they have it.
I'm talking about type 2 diabetes. It's a disease that can be hidden, because symptoms aren't always obvious, and some people have none at all.
Even if you don't experience symptoms, diabetes is causing serious damage in the background. Complications are as serious as they get: stroke, heart disease, blindness, lower limb amputations, kidney failure and early death.
Type 2 diabetes is related to insulin, a hormone we need to keep blood glucose at a healthy level. It happens when the pancreas fails to produce it or the body fails to respond to it.
As the condition develops, there's an increase in blood glucose levels. Over time, that causes damage to the nerves in the eyes, feet, kidneys and heart.
So how might we know if we could be at risk?
Some of the sneaky symptoms of type 2 diabetes can feel like symptoms of modern life. They include feeling tired and lacking energy; feeling thirsty; or feeling hungry often.
But it's worth having a closer look if you're experiencing other symptoms. They might include going to the toilet often, getting infections frequently that don't seem to heal or having poor eyesight or blurred vision.
The picture gets riskier when a couple of these symptoms combine with some of the risk factors for type 2 diabetes. They include age (over 40s are at higher risk), family history (if it's in your family, your risk is higher) or being of Maori, Asian, Middle Eastern or Pacific Island descent. Having high blood pressure is another risk factor.
Weight is the other thing that comes into play. Not everyone who develops type 2 diabetes is overweight, but being overweight is a real risk factor and a particular pattern of weight distribution is more risky: carrying weight around the middle.
Even if we're a "normal" weight, we can still suffer from what's known as normal weight obesity. Carrying this fat around the middle is more dangerous for us, metabolically, than having fat around the bum or thighs.
This is all quite gloomy, but the good news is that if it's picked up early – particularly at the pre-diabetes stage (also known as impaired glucose tolerance) when the glucose in your blood is higher than normal, but not high enough to be called diabetes – the disease can be managed, and there's the potential to stop it developing further.
And at early stages, that management revolves around food, exercise and lifestyle.
Addressing the weight issue is the hardest but potentially most effective step here. Diabetes experts say there's no one way to do this. Some people find success with lower-carb diets; others with intermittent fasting and others with a more moderate Mediterranean-style diet.
The broad recommendations for eating with type 2 diabetes are the same as for all of us: lots of whole plant foods, not too much processed food and keeping an eye on serving sizes and added sugars.
How that looks in practice is different for everyone. As we know, what we eat is affected by many things, including budget, family situation, taste, culture and lifestyle. Ultimately there's no one-size-fits-all diet for diabetes.
We know exercise is super-beneficial for body and mind so finding ways to move the body every day will have long-term benefits.
And obviously if you smoke, quitting is a priority. If you drink alcohol, cutting down can only be good.
While type 2 diabetes is a "lifestyle" disease that develops over time, type 1 diabetes is different: it can develop at any time, including in children, and has nothing to do with lifestyle. It's usually pretty sudden, though, happening within days or weeks rather than years.
It's worth knowing the unusual symptoms that might signal type 1 diabetes because if it's not picked up quickly there can be serious, even fatal, consequences.
They include excessive thirst, passing more urine than normal, weight loss, extreme tiredness, extreme hunger and poor concentration.
Lesser-known symptoms include abdominal pain, nausea, vomiting, skin infections, thrush and mood changes.
The bottom line here is: listen to your body. Most of us know when things are not quite right, and we know when things are not right with our kids, too. If any of the above is ringing alarm bells – even tiny ones – it's really worth getting it checked out.
• November is Diabetes Action Month. For more info, www.diabetes.org.nz