WHEN to Eat [Data Driven Fasting FAQ Part 4]

This section of the DDF FAQs explains how your body uses the food you eat and how your glucose and fat fuel tanks interact.     

4.1 When Should I Test My Blood Glucose After Eating?

In Data-Driven Fasting, testing 1 – 2 hours after you start eating will be fine.  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 chat will give you an understanding of whether you need to dial back your carbohydrate intake to manage hunger when your blood glucose comes back down.  The rate your blood glucose rises and falls after a meal will depend on what you are eating 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 you eat to see when your blood sugar peaks with the meals you typically eat. 

In Data-Driven Fasting, 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) AND your blood glucose rises above the normal healthy range, and it takes a long time to drop below your trigger.  If this is the case for you, you should consider eating less of that meal next time. 

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. Striving for near-linear 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 125,761 days of data from 34,519 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 and 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.  

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, then you ideally wouldn’t skip that meal.  Dinner could then be your Main Meal, and you can treat the other meals as Discretionary Meals.  

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 routine of one/two or two/three meals per day .  Many people who previously stalled out on OMAD find they 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 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!

If you find you are not losing weight with less than 1.5 meals per day on average, we suggest you review your food quality and work to increase the satiety value of the food you are eating (i.e., increase protein and reduce foods higher in energy from fats and carbs).

Nutrient-dense meals ensure you get the nutrients you need when you eat to feel more satisfied and less likely to overeat. 

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 decide to delay eating until your blood glucose comes down in the afternoon or before dinner. 

However, you may find you are even hungrier later that evening and find yourself losing control and bingeing again. This is particularly a concern if you see your waking blood glucose trending up. 

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 so you are less hungry at night.  You can also increase the amount of energy in your dinner, so you’re less likely to be raiding the fridge later. 

Another option is to lock in an earlier Main Meal that you will eat every day. You can then use your blood glucose trigger to decide if you will eat the other meals.

Our data analysis suggests that we tend to eat fewer calories if we spread our food out over two meals rather than compressing them into one.  However, if you find that OMAD works for you, that’s fine as long as you get adequate nutrients (particularly protein) in your narrow eating window. Many people alternate between one and two meals per day as their trigger lowers. 

If you find you are averaging less than 1.5 meals per day, you should review the quality of the food you are eating.  You can use our Free 7-Day Nutrient Clarity Challenge to review your current diet and find some new foods and meals that align with your goals.

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 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 have to have ‘breakfast’ first thing in the morning, it appears to be ideal to front-load your calories towards your first meal of the day, if possible, rather than eating your biggest meal right before you go to bed. This is known as early time-restricted feeding (eTRF). 

Not only are you more insulin sensitive earlier in the day, but you are also 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 of your energy at your first meal to synchronise your eating with your circadian rhythm. 

If you are finding 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 actually hungry. 

The goal of Data-Driven Fasting is to eat when you are hungry AND require fuel – not just when your blood glucose is below Your trigger. 

If you are above your Personal Fat Threshold, you will likely see more elevated blood glucose in the morning. However, some people find that their blood glucose is below their trigger when they wake and wonder if they should eat.

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 a LOT of 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 sustainably deplete your glucose stores over time.
  • When you eat, you don’t want to see your BG go above the ‘upper limit’ FULL line. 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 here, 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 fuel from protein and nutrients rather than 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. However, keep in mind that waking BG can go up initially as insulin lowers and you start to release stored energy. In time, it will settle down as you chase your trigger.
  • 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. In addition, focusing on protein and nutrients when you eat will help you manage satiety.
  • After a while, you will start to see the long-term patterns in your metabolism and when you need to refuel.  In the example below, we can see that the lowest blood glucose is in the afternoon.  Hence, this would be the ideal time for a solid meal, perhaps with a few more carbohydrates.  However, when blood sugars are higher earlier in the day, a protein-focused meal with fewer carbohydrates would be ideal. 

4.8 How Can I Plan Ahead With DDF?

In the first few days of the Data-Driven Fasting Challenge, you will use your blood glucose to delay meals and decide when to eat. Later, you will learn to lock in your Main Meal with Discretionary Meals based on your blood glucose. 

If your blood glucose is consistently above your trigger today, then it will be a safe bet that you should plan for one less meal tomorrow. Before long, you should fall into a new routine that you can follow most of the time, regardless of your testing. You can use your testing to ensure that what you are doing is working for you and decide if you need to refine it further.