Meal Timing Insights: When to Eat for Optimal Health

Embark on an enlightening journey into the core of meal timing with our insightful guide. Here at Optimising Nutrition, we unravel the science behind Data-Driven Fasting, shedding light on the crucial relationship between when you eat and your glucose levels post-meal.

This piece illuminates how adeptly managing your meal schedule, in sync with your body’s natural rhythms, can lead to better glucose regulation after eating, improved metabolism, and a transformative impact on your overall well-being. Armed with data-driven insights and practical tips, we aim to empower you with the knowledge required to make informed decisions around meal timing.

Delve deeper into understanding your body’s unique responses to food, and unlock the doors to an elevated state of health and vitality.

4.1 When Should I Test My Blood Glucose After Eating?

In the first week or so of the Data-Driven Fasting Challenge, checking if you’re overfilling your glucose fuel tank based on your blood sugar 1-2 hours after you eat can be helpful. However, given that the main focus is on premeal blood sugars, you don’t need to stress about the exact timing. 

After you log a few post-meal blood glucose values, the trend in your hourly glucose chart will help you understand whether you need to dial back your carbohydrate intake to manage hunger when your blood glucose comes back down (i.e., reactive hypoglycaemia). 

While many people want to know exactly when to test to find the maximum value after eating, the rate at which your blood glucose rises and falls after a meal depends on what you eat and your unique metabolism.

As shown in the chart below, blood glucose rises quickly after a high-carb, low-fat meal (green line), while it will increase more slowly and incrementally after a high-fat meal (red line).  If you’re curious, you could test before and then one, two and three hours after eating to see when your blood sugar peaks with the meals you eat. 

In DDF, all we are trying to do is:

  • find which meals raise your blood glucose the most to determine which ones you might need to avoid in the future,
  • identify when you are most insulin sensitive vs. insulin resistant to optimise meal timing (e.g., if your blood glucose rises the most at night and less in the morning, you might benefit from shifting your meals earlier), and
  • understand if you need to worry about carbs raising your blood glucose or if you should just be focusing on more satiating, nutrient-dense foods and meals. 

You don’t need to be too concerned unless a meal raises your blood glucose by more than 1.6 mmol/L (30 mg/dL).  This is especially true if your blood sugars also take a long time to return to your trigger.  If this is the case for you, you should consider eating less of that meal next time.

For reference, as shown in the chart below, the average rise in glucose after meals is 16 mg/dL or 0.9 mmol/L. 

While the blood glucose rollercoaster is bad, flat-line blood glucose should not be your goal. Stable blood glucose levels are a symptom of good metabolic health.  However, striving for flat-line blood sugars does not necessarily equal a healthy metabolism. While we can achieve stable blood glucose with a low-carb, high-fat diet (i.e., symptom management), reversing diabetes and improved metabolic health requires reduced body fat levels. 

While higher-fat foods will cause a smaller rise in blood glucose initially after meals, you need to balance adequate nutrition with stable blood glucose. As shown in the chart below from our analysis of data from people using Nutrient Optimiser, very high-fat foods tend not to be as nutritious. 

In terms of satiety, people tend to consume fewer calories when they reduce the energy from fat in their diet.  While you don’t need to swing from one extreme to another, working your way from where you are now to 40% dietary fat may be helpful if you want to lose body fat.

When testing your blood glucose after meals, keep in mind that:

  • fast-acting carbs will raise your blood glucose quickly. However, they may also come down quickly,
  • high-fat meals will help you achieve more stable blood glucose, but they may stay elevated and delay when you are ‘allowed’ to eat again,
  • meals that have a similar proportion of fat and carbs with low protein (e.g., cookies, croissants, milk chocolate, etc.) will fill both your fat and glucose stores, keep your blood glucose elevated for much longer, and
  • nutritious foods and meals that contain a higher percentage of protein will give your body what it needs with less energy and allow your body to draw down on its fuel stores.  

So, while dialling your intake of refined carbohydrates can be helpful if they rise a lot, you don’t need to go keto to succeed with DDF.  Our analysis of data from Optimisers suggests that reducing either carbs or fat or both will increase satiety and help with weight loss. 

For more details, see Low-Carb vs. Low-Fat:  What’s Best for Weight Loss, Satiety, Nutrient Density, and Long-Term Adherence?

4.2 How Can I Integrate Data-Driven Fasting into My Daily Routine?

As you progress with Data-Driven Fasting, we encourage you to fit your eating schedule around your regular work and family routine.  For example, if you typically eat dinner with the family, you wouldn’t skip that meal.  Instead, dinner could be your Main Meal, and you can treat the other meals as Discretionary Meals.  

After a few weeks, it’s ideal if you fall into a reasonably consistent routine and use your glucose to guide what and how much you eat.  For more details, see Data-Driven Fasting by the Clock for Long-Term Success.

4.3 How Many Meals Per Day Should I Eat?  

As you use your blood glucose to guide your progress, you should find that you quickly cut back on discretionary snacks.   Our analysis found that people tend to eat fewer calories when they eat two meals per day.

We tend to choose more energy-dense foods when we’re ravenous, so we often eat more with one meal a day than two.  It is also easier to meet your vitamin, mineral, and protein needs if you spread your food intake across two meals rather than trying to get it all in at once. 

Many older or less active people find that alternating between one and two meals a day based on their blood glucose guides them to long-term success.  However, if you’re active or trying to build muscle, more meals may be required.

You don’t have to jump to two meals a day immediately.  However, you may settle on a manageable daily routine of one/two or two/three meals.  Many people who previously stalled out on OMAD feel a lot better and restart their weight loss when they settle on a routine of two meals per day rather than one. 

If you find that two meals per day are still not working for you, we suggest you decrease the size of those meals and try to dial back carbs and/or fat rather than skipping full days of eating unless you can ensure you can avoid eating energy-dense, hyper-palatable foods after not eating for 36 hours!

Nutrient-dense meals ensure you get the nutrients you need when you eat to feel more satisfied, reduce your cravings and are less likely to overeat.  For some inspiration on what to eat, see:

4.4 How Do I Stop Snacking at Night?

One possible scenario with Data-Driven Fasting is that you will eat a big dinner, check your blood glucose in the morning, and find it is above your trigger.  You then delay eating until your blood glucose decreases in the afternoon or before dinner. 

However, you may be even hungrier later that evening and find yourself losing control and bingeing again.  This is particularly a concern if your waking blood glucose is trending up because you’re eating more at night. 

If you are reaching for energy-dense foods because you are too hungry after not eating all day, we recommend having a more substantial, protein-focused meal earlier in the day, even if your glucose is just above your trigger, so you are less hungry at night. 

You can also try increasing the size of your dinner so you’re less likely to be raiding the fridge later.  When you’re hungry later, you can check your glucose to see if you are below trigger. 

If your glucose is still above your current trigger, you know you don’t need the snack.  When you make the data-driven decision to skip the snack, you’ll find yourself hungrier earlier.  Before long, this will lead to making better food choices in the morning and less snacking at night.  However, if your glucose is below your trigger and you’re hungry before bed, you can enjoy a little extra something, guilt-free! 

As shown in the chart below from our analysis of half a million days of MyFitnessPal data, people who eat breakfast and lunch tend to eat less than those who eat lunch and dinner.  This aligns with other studies, like this one, that show that front-loading your calories leads to greater satiety and eating less. 

You should also increase nutrient density and protein % by dialling back foods that add the most dietary fat to allow your body to use stored body fat.  Instead of jumping from one extreme to the other, it’s better to slowly increase your protein percentage towards 40% or more of your calories for maximum satiety and fat loss while minimising the loss of precious lean mass. 

If you’re interested in pursuing this, we recommend trying out Macros Masterclass to tweak your balance of protein, carbs and fat to continue your journey after the Data-Driven Fasting Challenge

4.5 Eat ‘Breakfast’ Like A King

While you don’t need ‘breakfast’ first thing in the morning, it appears ideal to front-load your calories towards your first meal rather than eating your biggest meal right before bed. This is known as early time-restricted feeding (eTRF). 

You are more insulin-sensitive earlier in the day and more likely to use the food you just ate to fuel your activity rather than storing it while you sleep.  So, if your schedule allows it, try to eat most of your food when the sun is up and emphasise more energy at your first meal to synchronise your eating with your circadian rhythm. 

If you find you are overeating at night and your waking blood glucose is not coming down, it might be worth locking in a protein-focused Main Meal earlier in the day, even if your blood glucose is still above your trigger.  

4.6 If My Blood Glucose Is Below My Trigger When I Wake, Should I Eat?

No.  Especially if you’re not hungry. 

With Data-Driven Fasting, we use your glucose to validate your hunger and need to re-fuel.  

Even if your blood glucose is below your trigger when you wake, you should wait until you are hungry, and your blood glucose is below your trigger. 

If your blood glucose tends to rise through the day, locking in a protein-focused Main Meal earlier when you feel hungry and then using your pre-meal trigger for other discretionary meals may also help.  

4.7 How to Use Your Hourly Glucose Chart

Your hourly glucose chart in the DDF app can give you many insights. 

  • Think of the trigger line as a sign that you are running LOW and need to refuel. 
  • You don’t want your BG to go too far below your current trigger because your hunger will drive you to eat anything and everything (at the expense of food quality).
  • As you slowly chase a lower trigger, you will continue to deplete your glucose stores over time sustainably.
  • You don’t want your BG to go above the ‘upper limit’ FULL line when you eat. This is a sign that you overfilled your glucose and (or) your fat fuel tanks are full (i.e., adipose tissue on your bum and belly), and fuel is backing up in your system. Try to reduce or avoid foods that boost your post-meal glucose above this threshold. Reducing processed carbs will help, but don’t simply swap them for dietary fat if you want to lose body fat.
  • If your pre-meal values are higher in the morning than later in the day, you should prioritise protein and nutrients over fat or carbs in the morning.  This is because higher % protein meals tend to help your BG to go down rather than up. Conversely, you could add more carbs to your first meal if your pre-meal values are lower earlier in the day.
  • If your waking BG is high, you should consider ‘closing your window’ a little earlier and (or) eating a little less late at night.  
  • If your trigger starts to stabilise at a lower level and weight loss slows, try to dial back dietary fat to allow your body to use stored fat.  Focusing on protein and nutrients when you eat will help you manage satiety while allowing your body to use your body fat for fuel.
  • After a while, you will start to see the long-term patterns in your metabolism and when you need to refuel.