The Powerful Premeal Blood Glucose: The Unsung Hero of Optimising Your Weight and Metabolic Health

While your fasting glucose gets most of the attention from your doctor, and the keto biohackers like to focus on stabilising their glucose after they eat, your glucose before you eat is the unsung hero and the key to your metabolic health. 

As you will see in this article, not only is your premeal glucose tightly correlated with many important markers of metabolic health, but it’s also the one number you can actively manage simply by optimising what and when you eat. 

In our Data-Driven Fasting Challenges, many Optimisers wonder what premeal glucose number they should aim for or how low is too low. 

To answer these important questions, let’s delve into the data to the data. 

As a bonus, we’ll also show you how to use your premeal glucose to take charge of your weight and metabolic health. 

What is Premeal Glucose?

Your premeal glucose is your blood glucose just before you eat.  Meanwhile,

  • your fasting glucose (or waking glucose) is your glucose when you wake after an overnight fast, and
  • your post-meal (or post-prandial glucose) is your glucose after you eat.  

What is the Normal Range for Premeal Glucose? 

Over the past three years, 6,517 Optimisers have logged 458,087 premeal glucose values in the Data-Driven Fasting app.  Many are eager to know how they compare to ‘normal’ levels. 

The average premeal glucose for all our Optimisers is 95 mg/dL (5.3 mmol/L). 

The charts below show the distribution of premeal glucose values, with a

  • 15th percentile value of 81 mg/dL (4.5 mmol/L) and an
  • 85th percentile of 106 mg/dL (5.9 mmol/L). 

But, as you will see, there is a difference between normal and optimal. 

For all the details from our data, read on.

What is the Optimal Target for Premeal Glucose? 

Most of the time, blood glucose targets are used to diagnose and manage pre-diabetes or type 2 diabetes, not optimise your metabolic health.  To understand the glucose levels that align with more optimal metabolic health, let’s look at how premeal glucose aligns with other markers we collect in the Data-Driven Fasting app

Premeal Glucose vs Body Weight  

The first chart shows that premeal glucose aligns closely with body weight.  People with a lower glucose before they eat tend to be lighter. 

Due to oxidative priority, when your glucose is high, your body will prioritise using the glucose in your blood for fuel.  But as you lower your glucose, the body turns to your stored fat for fuel. 

Premeal Glucose vs Body Mass Index

A lower premeal glucose also aligns with a lower body mass index (BMI)

  • A premeal glucose of 101 mg/dL (5.6 mmol/L) aligns with a BMI of 30, which is the cut-off between being overweight and obese. 
  • Meanwhile, a much lower premeal glucose of around 73 mg/dL (4.1 mmol/L) aligns with a ‘normal’, healthy BMI. 

Premeal Glucose vs Waist-to-Height Ratio

The glucose before you eat aligns with your waist-to-height ratio. 

  • A premeal glucose of 108 mg/dL (6.0 mmol/L) aligns with the cut-off between a “high-risk” and “increased risk” waist-to-height ratio. 
  • Meanwhile, a much lower premeal glucose of 73 mg/dL (4.1 mmol/L) aligns with the cut-off between “increased risk” and “healthy” waist-to-height ratio. 

Body Fat (%)

A higher premeal glucose also aligns with a higher body fat (%).  However, reducing the glucose in your blood is not simply a matter of reducing the carbohydrates in your diet.  It’s also related to the amount of fat stored in your body. 

Note: Men tend to have a lower body fat % than females. However, the chart above shows all our data combined, which is around 80% female, with a high proportion of postmenopausal women.

Post Meal (Post Prandial) Glucose

The chart below shows that premeal glucose is closely correlated with post-meal glucose. 

Many people focus on changing what they eat to reduce their rise in glucose after eating.  However, while reducing the carbohydrates in your diet can be helpful, simply swapping carbohydrates for fat is largely symptom management and does little to address the root cause of poor metabolic health — energy toxicity.  However, the good news is that by actively managing our premeal glucose, we automatically manage our post-meal glucose.  

Blood Pressure

Our data also shows that premeal glucose is also correlated with blood pressure.  A premeal glucose of 91 mg/dL (5.1 mmol/L) aligns with the cut-off between normal and elevated systolic blood pressure. 

Fasting Blood Glucose

Finally, premeal glucose is also closely related to fasting glucose. 

  • A premeal glucose of 120 mg/dL (6.6 mmol/L) aligns with the cut-off for pre-diabetes/type 2 diabetes cut-off of 126 mmol/L (7.0 mmol/L).  
  • Meanwhile, a premeal glucose of less than 92 mg/dL (5.1 mmol/L) aligns with the cut-off between pre-diabetes and normal glucose control 100 mg/dL (5.6 mmol/L). 

Why is it Important to Manage Your Premeal Glucose?

The glucose after you eat is heavily influenced by the balance of carbohydrates vs fat in your diet.  However, the glucose before you eat is a much better indication of how much energy you have stored in your body. 

The image below depicts the major fuel tanks in your body.  These fuel tanks are somewhat separate but connected.  Due to oxidative priority, the glucose in your body must be used before fat.  If your body fat and liver are full, excess energy will ‘back up’ into your bloodstream and show up as elevated blood glucose levels. 

While we always use some mixture of fat and glucose for fuel, we can tip the balance towards fat oxidation by managing premeal glucose. 

  • Once you deplete the glucose in your bloodstream, you ‘unlock’ the stored glycogen in your liver. 
  • Then, once you deplete the excess glycogen in your liver, your body will use the fat in your blood. 
  • Finally, so long as you’re not overconsuming dietary fat, your body will burn more stored fat for fuel.  As you deplete excess body fat, you will also see less glucose in your blood. 

Unfortunately, draining the excess energy from your body is not an overnight process.  But be assured that when your blood glucose is a little lower than normal before you eat, you’ll be tapping into your stored glucose (glycogen) and, subsequently, the other fuel tanks.

Progressively lowering your premeal glucose, as we do in the Data-Driven Fasting Challenge, is the first step in the process. Once your premeal glucose is lower, your body can get on with using your stored body fat.

How Can I Monitor My Premeal Glucose? 

An accurate glucometer, like the Contour Next, is the best way to monitor and manage your premeal glucose.  Some people use continuous glucose monitors in our Data-Driven Fasting Challenges, but most find the glucometer more consistent, accurate, and cheaper. 

With the guidance of the DDF app, Optimisers check their glucose when hungry to validate their hunger and their need to refuel.  This process is known as hunger training

Before long, Optimisers become better able to calibrate their hunger with their blood glucose levels before they eat, empowering them to understand when they need to eat. 

As they continue, the Data-Driven Fasting app progressively lowers their premeal glucose trigger to ensure they continue to make progress, draining both their excess stored glucose and body fat. 

How Often Should I Check My Premeal Glucose?

In our Data-Driven Fasting Challenge, Optimisers only need to test their glucose when hungry.  If their glucose exceeds their current trigger, we recommend waiting at least half an hour before checking again. 

In the first week or so, it is useful to check post-meal glucose to ensure you are not overfilling your glucose fuel tank with excessive amounts of refined carbohydrates. 

It can also be useful to check your waking glucose occasionally to monitor your long-term progress. 

But before long, most people settle into a routine with a regular meal pattern that ensures a sustainable energy deficit that aligns with long-term fat loss. 

What Can Affect My Premeal Glucose?

The image below shows the ideal scenario: your glucose rises by less than 30 mg/dL (1.6 mmol/L) after eating and then returning to your trigger before eating again.  However, other things besides food, like stress, exercise, and pain, can affect your glucose. 

For more details, see:

How Long Does it Take to Reduce My Premeal Glucose? 

When they learn the importance of managing their premeal glucose, many people are eager to bring it down as soon as possible.  But the reality is that it’s often a long-term game.  Pushing too hard too soon inevitably leads to excessive hunger and rebound binging as your body fights the self-inflicted starvation.

Our goal in Data-Driven Fasting is to guide our Optimisers to lose weight at a healthy, sustainable rate of 0.5 to 1.0% per week.  This ensures that the loss of precious lean mass is minimised. 

The Data-Driven Fasting app automatically lowers your premeal trigger at a maximum rate of 0.5% per day based on your premeal glucose over the past week. 

We also encourage Optimisers to take a break to practice maintaining their weight after each round of the DDF Challenge.  They then restart their three-day baseline period at the start of each challenge, chasing a lower premeal trigger all over again.

Case Study: Muffy

Muffy’s chart, shown below, shows what this can look like over the long term.  The blue line shows the premeal glucose values logged in the DDF app, while the aqua line shows the trigger, which lowers in each successive challenge. 

The chart below shows her weight loss during this period, starting at 200 lbs and falling to 130 lbs at a rate of around 1.0% per week. 

As we might expect from the charts at the start of this article, Muffy’s waking glucose fell into line, moving from the upper end of the pre-diabetes range to the normal healthy range. 

Her body fat and waist-to-height ratio also dropped as she chased a lower premeal trigger. 

As they say, a picture paints a thousand words, so here’s the before and after. 

You can read more about Muffy’s inspiring story here and check out the results from other Optimisers over the years here


Your glucose before you eat can empower you to make informed dietary choices, leading to weight loss and optimised metabolic health.  

An incremental, data-driven approach can empower you to actively manage your glucose levels throughout the day and improve your health markers such as body weight, BMI, and blood pressure.   

Action Steps