Image copyright BBC/Doctor in the House

Type 2 diabetes affects approximately 3.5 million people in this country and is thought to cost the UK around £20bn per year in both direct and indirect costs.

This is a staggering amount of money spent on a condition largely caused by our lifestyle choices and environment.

On Doctor in the House, I try to help 39-year-old La-Vern. Her mother, Doreen, already has type 2 diabetes and is worried that La-Vern is going down the same route.

La-Vern is a busy, single mother who does two jobs and, as a result, is exhausted and stressed.

She has not yet crossed our diagnostic threshold where we would say she has type 2 diabetes, but her blood sugar and fasting insulin levels are not "normal" either. Her results suggested that she was on the road towards type 2 diabetes.

This is an ideal opportunity to practise true preventive medicine. Type 2 diabetes is a late event. By the time you get a diagnosis, things will have been going wrong in your body for many years.

La-Vern's symptoms of fatigue have already affected her quality of life. However, her lifestyle is not only causing her to feel unwell, but is driving her towards a type 2 diabetes diagnosis further down the line.

Resistance

This is one of the big problems in medicine today - things are often said to be black or white, normal or abnormal - but what about optimal?

I am an advocate for trying to recognise problems before they happen. Why should we wait for people to get a type 2 diabetes diagnosis before we take action?

Type 2 diabetes is often viewed as a dietary illness. That is partially true as diet is a big contributor.

However, other lifestyle factors such as insufficient sleep, long-term stress, and inappropriate physical activity all contribute, as well. For many of my patients, addressing these factors can be as important as their food choices.

Image copyright BBC/Doctor in the House Image caption La-Vern's mum Doreen already has type 2 diabetes and worries that her daughter will also develop it

Most cases of type 2 diabetes are caused by a condition called insulin resistance.

Insulin is an important hormone and one of its functions is to keep your blood sugar tightly controlled. If you are in optimal health and not insulin resistant, a sugary bowl of breakfast cereal will cause your blood sugar to go up. Your body will then release a little bit of insulin to bring it back down again.

As your health deteriorates and you start to become insulin-resistant, you need more and more insulin to keep your blood sugar under control. Your body has become deaf to insulin's sound.

It is a little bit like alcohol - the very first time you have a drink, it may only take a few sips of wine to feel tipsy but as you become accustomed to drinking more and more, you need more and more alcohol to have the same effect - your body has become resistant to the effects of the alcohol.

This is similar to what happens in insulin resistance.

This raised level of insulin can itself cause many problems. And when the insulin can no longer keep your blood sugar under control - at that point, we give you a diagnosis of type 2 diabetes.

As I explained in a TED talk, there is a problem with blood sugar in type 2 diabetes, but it is not a blood sugar problem. By the time your blood sugar goes into the diabetic range, things have been going wrong in your body for many years.

The four areas of treatment I focused on with La-Vern are the same four areas I look at with almost all of my patients: food, movement, stress and sleep. Problems in these areas can all contribute to the development of insulin resistance.

Food

The main change I made with La-Vern's diet was to cut out highly processed junk food. Because of her insulin resistance, she was unable to efficiently process foods that quickly converted to sugar in her body, so I advised her to eliminate refined carbohydrates in her diet such as sugary breakfast cereals, white rice and bread.

I encouraged her to increase her intake of healthy, natural fats such as avocados, nuts, and olives as well as healthy protein sources such as salmon and anchovies.

Image copyright kizilkayaphotos Image caption Being on your phone late at night can affect your sleep

Sleep

La-Vern had trouble sleeping and this was contributing to her exhaustion. However, sleep deprivation can also cause insulin resistance. Like many of us, La-Vern was glued to her smartphone every evening. This late-night usage can cause major sleep issues. There are two main reasons for this:

Light - The blue light emitted from smartphones is not seen in nature in the evening. This blue light can suppress your body's melatonin levels, a critical hormone that gets you to sleep.

- The blue light emitted from smartphones is not seen in nature in the evening. This blue light can suppress your body's melatonin levels, a critical hormone that gets you to sleep. Switching off - An inability to switch off is one of the biggest causes of sleep disruption. Staying "on" while mindlessly scrolling through social media feeds and emails is a sure-fire way to keep your mind active. This in turn can affect your sleep.

I advised La-Vern to switch off all electronic screens at least one hour before going to bed. I also gave her some amber glasses to wear in the evening to reduce the amount of blue light hitting her eyes.

These small changes had an immediate impact - her sleep improved and her energy levels increased.

3. Exercise and stress

La-Vern is a very typical case of what I see in my practice. She's extremely busy - a single mother working two jobs and highly stressed.

I explained to La-Vern how her energy reserve is a bit like a bank account - you cannot keep making withdrawals without going into overdraft.

She had very little energy reserve left with the demands of being a single mum, her two jobs and lack of sleep.

Whatever time she did have left, she spent going to the gym three times per week for an intense one-hour workout session, which left her feeling drained.

La-Vern was simply doing too much and her exercise regime was actually putting more stress on her body. This is a common problem these days - we have been conditioned to think that more exercise is always better.

I persuaded La-Vern to swap these intense workouts for yoga, a more restorative practice. This was life-changing. At the end of her yoga session, La-Vern not only felt as though she had worked out but also felt rejuvenated and energised. Plus, it was the only "switch off" time she had all week.

By addressing these four areas of health - food, movement, sleep and stress - I not only helped La-Vern feel significantly better, but, just as importantly, I've reduced her risk of following her mother down the road towards type 2 diabetes.

La-Vern is unstinting in her praise of Dr Chatterjee. She says he "saved" her life.

She adds: "[That's} a profound statement I know; however he came into our lives at such a crucial time. By sharing his knowledge he has given me, my mum and my family the tools to implement very subtle changes that have literally turned our lives around.

"As humans we take certain things for granted but do we realise how such things like stress, the food we eat and a lack of sleep, the quality of the sleep actually has such a detrimental impact on the way we think, our overall health and general well-being? Until now, I certainly did not.

"Our lack of understanding meant we were tackling aspects of our lives and health believing it was for the best when in fact we were doing more harm than good. With the benefit of hindsight, this is quite a scary concept.

"We felt truly blessed to have had the opportunity to have Dr Chatterjee in our lives. He is a very wise, caring and such a genuine person and we are so grateful to him for helping us to bring about changes that are having such a positive impact."

Too much of our focus in medicine is reactive and treatment kicks in only once you have a disease.

If there is any hope of saving our NHS, we have to be much more proactive at recognising and treating problems early on.

The future of healthcare needs to be preventive and personalised.

It's what I call progressive medicine, and there is an ever-growing need for us to practise it right now. Type 2 diabetes: a real need for preventive medicine.

Doctor in the House is on BBC One on Tuesday 27 June at, 10.45pm.

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