5 Ways To Prevent Post-Meal Blood Sugar Spikes

You bolused, you ate, then an hour later, your sugar is climbing anyway. If that sequence sounds familiar, you’re not doing anything wrong—food digestion and insulin action (how fast your insulin starts working in your body) just don’t always move at the same pace, whether you live with type 1 diabetes (T1D) or type 2 diabetes (T2D) and use mealtime insulin.

This guide covers ways to help close that gap, from insulin timing to eating in a different order to increasing post-meal activity. None are a universal fix or a replacement for a conversation with your healthcare provider (HCP), however. Always consult them before you change your routine, especially when it involves your insulin. Use the tips in this guide as a jumping-off point for a conversation.

1. Pre-bolus your insulin to avoid post-meal spikes

If you take fast- or rapid-acting insulin (by pen, syringe or pump), pre-bolusing is the standard advice for meals that are roughly moderate in carbs, fat and protein. I.e., they have a good balance of nutrients!

A pre-bolus just means taking your mealtime dose 5 to 15 minutes before you eat, not seconds before the fork hits your plate, then your mouth. The only time this isn’t the case is with inhaled insulin, which must be taken with the first bite of food because of how quickly it works. Today’s fast-acting insulins take about 15 minutes to start working after injection and typically peak around the one-hour mark. Inhaled insulin takes about 10 minutes to start working and peaks within about 40 minutes. So what’s important is that you give the insulin that head start, and it’s more likely to be active in your system right as your food starts digesting, which is the whole game here.

Seasoned vets and newbies need this reminder. It can be an easy habit to drop the longer you live with T1D, but it’s super important to keep up if you want to avoid those pesky post-meal spikes.

2. Don’t pre-bolus under special circumstances

Pre-bolusing works well for that moderate middle ground, but it gets riskier with the extremes. Let us explain!

A high-carb, high-fat meal like pizza, cake or Chinese takeout can take hours to fully digest, so bolusing early with your full insulin dose and eating on schedule can leave insulin peaking well before the food does, which sets up a low. Then you end up eating more than expected, and your blood sugar spikes even more hours later.

Talk to your healthcare team about splitting up your insulin doses so you can enjoy these foods safely in moderation. On the other hand, a low-carb, high-fat, high-protein plate has the opposite problem—digestion is slow across the board, so pre-bolusing may not be necessary, or safe, at all.

Always consult your HCP about the best times for you to pre-bolus based on your insulin dosing strategy, what type of food you’re eating, how your body responds, and your habits and post-meal actions (like whether you take a walk after eating—but we’ll get to that later).

3. Inhaled insulin plays by different rules: pre-bolus right before you eat if you use it

Inhaled insulin is a less commonly discussed option, but it solves the pre-bolus puzzle differently. It starts working within about 12 minutes and clears your system within 90 minutes to three hours, depending on the dose. It’s fast enough that you can dose right as you start eating instead of guessing 15 minutes ahead.

That speed makes it worth considering for T1D or insulin-dependent T2D when your eating schedule isn’t predictable. 

Things that can make eating and insulin timing unpredictable include:

• Ordering at a restaurant
• Grabbing lunch between meetings
• Eating at a social gathering, like a work event, friend or extended family member’s home
• Or just any situation where you genuinely don’t know when the food’s going to show up

Ask your HCP whether it makes sense to add inhaled insulin to your routine if your schedule is often unpredictable.

4. Hack your plate: eat in this order

Injected iInsulin timing isn’t the only thing that matters. What you eat first at a meal changes how much your blood sugar rises, independent of the food itself. In one clinical trial, adults with T2D who ate vegetables and protein before carbohydrates, instead of eating everything together, or carbs first,  cut their average post-meal glucose spike by 44%. Tracked over 12 days of ordinary eating, that same food order pushed their time in target range from 78.6% up to 84.8%.

This isn’t about restricting what’s on your plate—it’s about eating it in an order that makes sense for your physiology. Save the rice, bread or dessert for last. Eat your vegetables and protein first. (Yes, mom and dad were right about that.) Honestly, it kind of makes sense, right? Save the best—or the thing you like most—for last. It’s something to look forward to, and you can be proud you conquered the healthiest parts of your plate first.

It’s a small change that stacks well with the insulin-timing strategies mentioned throughout this guide. Eating a lower-glycemic plate in general, with balanced macronutrients and appropriate portion sizes, can help too, but everybody is different. Different foods and eating strategies may support your body. Through trial and error, you can find your ideal strategy! These recommendations can make it easier to nail it.

5. Move your body after you eat

A walk after eating is one of the simplest tools you can take advantage of, and it doesn’t require any insulin math. A 15- to 30-minute walk after your biggest meal of the day is a generally safe way to help your body use up some of that circulating glucose (sugar). Research backs this up. In one study of older adults, three separate 15-minute walks after meals improved 24-hour blood sugar stability more than one longer, continuous walk did.

If you take insulin, or another blood-sugar-lowering medication, the post-meal walk math is a bit different. Don’t avoid it—it’s still good for you—but carry fast-acting carbs before you head out like juice, glucose tabs, jelly beans or whatever works for you. Know the signs of a low before you’re in the middle of one.

Take it one step at a time

Trying to overhaul your whole routine could send you in the other direction. Take small steps in the right direction to form habits that stick. 

Try one of these steps at a time if that makes it feel more doable—here’s the “too long didn’t read” (TL;DR) version of every step we covered in this guide, plus a little more explanation:

• Pre-bolus: take your injected insulin 10 to 15 minutes before meals that are moderate in carbs and fat. Take your inhaled insulin with the first bite of food. Check with your HCP before doing this with high-fat or very low-carb meals, as explained earlier in this guide.
  
• Eat vegetables and protein first: save bread, rice or dessert (simple or complex carbs) for the end of the meal.
  
• Take a 15-minute walk: within an hour of your largest meal, carrying fast carbs if you’re on insulin.
  
• Log your post-meal numbers for two weeks: noting what you ate, when you dosed and what your blood sugar did. Patterns show up fast once you’re tracking them.
  
• Recheck your blood sugar levels about two hours after eating: the CDC’s general target at that mark is under 180 mg/dL (10.0 mmol/L), though your own target range may look different. If you’re unsure what yours should be, talk to your HCP so you can figure it out together.

Put this on a Post-it note or save it to your Notes app if it helps. Visual reminders can help you implement these new habits too.

Get support from your healthcare team to make these changes

A post-meal spike above 180 mg/dL (10.0 mmol/L) once in a while isn’t usually cause for alarm. But if that’s happening after most meals despite these adjustments, or you find yourself trading spikes for frequent lows once you start timing insulin differently, bring it up with your HCP as soon as possible. 

Don’t normalize post-meal spikes or drops. Even when you live with a form of insulin-dependent diabetes, you shouldn’t be encountering this all the time. Big blood sugar swings that are frequent can be exhausting and lead to diabetes burnout. This shouldn’t be your everyday. You can do better with your team’s support. Your insulin-to-carb ratio, correction factor or basal rates might just need a tune-up if you find yourself running into this. 

Don’t try to change everything on your own. Talk to your HCP first to figure out what to do. This will help you feel more confident and supported as you begin a new way to manage your diabetes. You can do it!

Finding what works for your body takes some trial and error. Want to connect with people living with T1D or T2D who get it? Join our Community Apps!