How to Use Diet to Prevent Diabetes


Insulin resistance is a key factor in the development of type 2 diabetes. It is also associated with Polycystic Ovary Syndrome (PCOS).

For clarification, type 2 diabetes is a metabolic disorder characterised by an imbalance in blood glucose levels, altered lipid profiles and high blood pressure. It usually presents as a combination of insulin resistance and deficiency.
PCOS is the most common endocrine disorder impacting people with ovaries of reproductive age and to be diagnosed with it there has to 2 out of 3 of the following:

  • Problems with ovulation
  • Biochemical or physical signs of hyperandrogenism (high levels of male hormones)
  • Polycystic ovaries (multiple cysts)

It is often associated with insulin resistance which can make the symptoms of hyperandrogenism worse (irregular periods, excess hair growth and acne).

Do I Need To Lose Weight To Improve Insulin Resistance?

We often hear that weight loss will improve insulin resistance. Whilst this isn’t incorrect, simply knowing this, doesn’t automatically mean we can achieve and maintain it.

We can’t ignore that there are consequences to our continued pursual of weight loss. Yet we often keep going because we’re made to feel guilty. Made to feel like we’re to blame for having these health issues in the first place.

It’s a little more complicated than that and there’s lots to consider.

In this blog, I am going to talk about the common diets used to ‘treat’ insulin resistance. We’ll explore whether it is possible to improve the management of insulin resistance and blood glucose levels in the absence of weight loss. Let’s first of all be clear on what insulin resistance is.

What Is Insulin Resistance?

Quick bit of biology then. Insulin is released from the pancreas in response to rising sugar (glucose) levels in the blood. Its role is to act as a key, opening up the doors of muscle and liver cells to allow glucose to pass in. This is where it is converted into energy. What isn’t needed for immediate energy is stored in the form of glycogen.

Insulin resistance isn’t to do with not having enough insulin (although insulin deficiency can develop as part of type 2 diabetes). The word ‘resistance’ refers to the fact that the cells that are supposed to respond to it by opening up their doors, stop listening. The body responds by releasing more insulin in the hope this will help. But we’re dealing with a rusty lock on those doors and it’s not easy.

Insulin is a storage hormone so lots of circulating insulin will tell the body to store. Whether this be glycogen or triggering fat cells to accept glucose and store it as fat, which creates a vicious cycle as it can cause weight gain– and this isn’t your fault!

If it goes on for a long time, the cells in the pancreas that produce insulin get overworked and insulin levels may start to decline.

How Do You Detect Insulin Resistance?

NICE guidance says that if fasting blood glucose is between 5.5-6.9mmol/l then this is suggestive of insulin resistance, the theory being that if fasted, blood glucose levels should be lower so if they’re staying above 5.5mmol/l, it shows the system is struggling to cope.

The other measure you may be familiar with is HbA1c.

With more glucose hanging around in the blood, it joins to haemoglobin – this HbA1c has a life of about 3 months so when tested, gives an idea of how much glucose has been in the blood in the previous 3 months. In type 2 diabetes the aim is to keep this under 48mmol/mol.

Drugs That Treat Insulin Resistance

If you have type 2 diabetes or PCOS you may have been prescribed medication to either improve your cells sensitivity or to help your body get rid of the glucose. I’ll talk about all that another time!

What Causes Insulin Resistance?

So, bottom line, does being fatter cause insulin resistance?

Higher body weights are associated with insulin resistance but the key word there is associated. We can’t say for sure that higher body weights cause insulin resistance, without also considering how much of a role insulin resistance plays in contributing to weight gain in the first place as we’ve just discussed.

Visceral fat (fat around our organs and therefore associated with weight gain around the middle) is more metabolically active and is definitely connected to disease risk. Risks such as diabetes and cardiovascular disease (as opposed to sub-cutaneous fat under our skin).

But there are lots of factors which influence what happens to our blood sugar (glucose) levels, how sensitive our body cells are to insulin and therefore how resistant we may become to the actions of insulin. These include:

  • Genetics
  • Family History
  • Ethnicity
  • Stress
  • Sleep
  • The balance of foods we eat or have access to eating in relation to all of those factors above.

We can sum this up to say how the genetic hand we’ve been dealt collides with the environment we find ourselves in has the potential to be the perfect storm, but it’s also a storm we can weather really well if we have the right tools, understanding and support and attitude.

What Does This Mean For The Person With Insulin Resistance?

So aside from someone with insulin resistance feeling it’s all their fault, we also have to consider how they’re feeling day to day. Despite there being glucose (fuel) in the blood, it’s not getting where it’s needed so tiredness is common. As far as the body is concerned, it still needs fuel. Appetite will also go up and there are strong links between the pathway that controls insulin and the pathway that controls leptin. This is the hormone that tells us we’re full. So, we might feel lethargic, hungry and confused – all while we’re being told to ‘diet hard!’ Not ideal.

So, now to the question,

Can You Reverse Insulin Resistance With Diet?

If you google that, it is likely you’ll get bombarded with keto or fasting information. These methods do work, but clearly not for everyone. Let’s look at the Direct trial which sought to find out if type 2 diabetes could be put into remission using a very low-calorie diet of 850 calories. Participants had 850 calories per day for 3 months. Followed by food reintroduction for 2 months and then a weight maintenance phase.

Let’s whizz to the conclusion at 2 years because this is what we really want to know. 45 out of 272 people that they had data on achieved a maintenance of at least 10kg and of these 29 achieved remissions. So, what about the other 243 people?

We have to consider the fall out from following such strict regimes and also whether they are sustainable long term, as weight cycling i.e. repeatedly losing and gaining weight can increase insulin resistance, is a predictor of type 2 diabetes development, increases stress levels and adds to emotional distress.

They do suit some people, but if they’re not suiting you it’s ok and it’s not your fault. Here’s 3 tips and things to consider:

Amounts of carbohydrate do make a difference to blood glucose levels independent of weight loss. Eating slow release, high fibre carbs in conjunction with protein and healthy fats helps to ease the pressure put on the cells. This doesn’t mean going very low carb or keto. Keeping carbs in the diet allows you to meet your fibre requirements. High fibre diets are associated with a reduced risk of developing diabetes.

Consider your relationship with exercise. If you’re insulin resistant and trying to maintain a strict calorie deficit, you’re going to find exercise mor effortful. Exercise is a treatment for insulin resistance irrespective of what you’re eating. Resistance training is particularly beneficial as it increases your muscle’s capacity to store glycogen.

If you feel the focus has become all about the diet. If you’re second guessing your every food decision and it’s stressing you out, just stop. Just pull back and look at what else might be contributing to your health and wellbeing. Sometimes the pursuit of weight loss can distract us from the stuff that really counts. Things like health behaviours and the right mindset that can actually improve our physical and mental wellbeing. Those things can reduce stress levels, regulate your blood glucose levels and give you more energy to move more. And most importantly, have a better quality of life.