Tame Those Post-Meal Spikes!
14 Strategies to Reduce High Blood Glucose After Eating
Michelle MacPhee, Diabetes-Mom
Post-meal blood sugar spikes (the temporary high blood glucose that occurs soon after eating) make our T1D kids feel crummy and threaten their long-term health. But take heart! We have the power to “flatten the curve!” Here we look at the 14 best tips regarding insulin, food and exercise that can help reduce the size and frequency of post-meal spikes, which will give our kids the best chance to feel good, protect long term health and reach their own potential.
Here are the most effective strategies to tame those fire-breathing post-meal BG spikes:
1. Just Take More Insulin???
Imagine a scenario where BG rises uncomfortably high at 2 hours but then returns to target (or close to) within 3 or 4 hours. What would happen if your child took more insulin for the same amount of carbs at the same meal tomorrow? Since most insulins start working at ~15 minutes, peak at 60 – 90 minutes, and last about 4 hours, then in this scenario, the extra insulin will likely lead to a low.
Instead, consider increasing the insulin dose for food only if blood glucose spikes and stays high 2 – 3 hours after eating; this is may indicate that the existing doses are not strong enough. (Or you may need to tweak the basal insulin rate...)
So if it’s not going to work to simply give more insulin, what can we do to reduce BG Spikes caused by food?
2. Let’s Dance!
A family walk after supper is a nice outing for everyone, and for your T1D child, physical activity after a meal has the added benefit of helping reduce the peak of his post-meal blood sugar. When we use our muscles to move and play soon after eating, insulin is absorbed faster, digestion is delayed (reducing the speed at which sugar enters the blood stream), and the glucose that is already in the blood is used up in the activity (working muscles need sugar!) Put together, these factors make physical activity one of the best strategies for improving blood glucose control after a meal.
In his article Strike the Spike,1,2 Gary Scheiner suggests “ten or 15 minutes (or more) of mild activity will usually get the job done. The key is to avoid sitting for extended periods of time after eating. Instead of reading, watching TV or working on the computer, go for a walk, shoot some hoops, or do some chores. Try to schedule your active tasks (housework, yard work, shopping, walking pets) for after meals. Also attempt to schedule your exercise sessions for after meals.”
So go ahead and play tag, ride a bike… waltz around the kitchen!
3. Banish Pre-Meal Lows
While avoiding hypoglycemia is a good idea in general, a low blood sugar impacts post-meal spikes in a particular way. When blood glucose dips into the low range (less than 4.0 mmol/L), the body helps with recovery from the low by speeding the movement of food from the stomach to the intestine, where it can be broken down into the sugar that the body so desperately needs at that time. However, if your child eats a meal or snack right after a low, then the food is digested more quickly than usual, which means it leaves the insulin behind in the dust even more than usual. This results in higher highs after the meal. For this reason, preventing lows is a key strategy for flattening the post-meal curve.
4. Give Insulin a Head Start
Often post-meal spikes result from a mismatch between insulin timing and the rate at which our food is digested. Some of the best strategies to manage these post-meal highs revolve around better matching insulin action to food. One of these strategies is Pre-Bolusing (giving the rapid-acting insulin bolus before eating).
Research has shown that simply delivering a mealtime bolus of rapid-acting insulin 15–20 minutes before a meal, compared with immediately before the meal, reduces post-meal blood glucose by about 30% (and is associated with less hypoglycemia, to boot!)3 Further, if you wait to deliver insulin until after you have eaten, then the food has too much of a head start; the insulin will not be able to catch up to counteract the effects of the food. For this reason, pre-bolusing is one of the most important things you can do to reduce post-meal spikes.
*Bear in mind that pre-bolusing may not be wise with young children because you may not be able to count on the amount that they will eat, or sometimes whether they will even eat at all! Pre-bolusing is also unwise if an individual has gastroparesis, in which the stomach empties more slowly; in this case, pre-bolusing is likely to lead to low blood glucose, as the insulin acts before the food does. If you’re uncertain, check with your child’s diabetes health care team to see if pre-bolusing is right for your child.
If your child is already pre-bolusing 15-20 minutes before eating but is still experiencing post-meal spikes, then he may need to take the meal insulin dose even earlier.
The ideal pre-bolus time could be more or less than 15 minutes, depending on what your blood sugar reading was before you ate, as well as the rate of digestion of the foods you are about to eat: you will pre-bolus for less time if your BG is on the lower end and/or if you’re about to eat foods that digest slowly; you will need to pre-bolus for longer if your BG is above target, and/or if you are about to eat foods that digest quickly. Which brings us to…
5. Tweak the Timing of Bolus Insulin
As we said, a 15-minute pre-bolus is a great starting point in terms of timing the dose of rapid-acting insulin to better match the digestion of food. But what if your child’s pre-meal BG is really high? It takes insulin 15 minutes to even start acting, so blood glucose won’t even budge in those first 15. Further, what if she’s about to eat watermelon? On the other hand, what if pasta is on the menu? Different circumstances require different timing of the meal insulin.
Gary Scheiner (MS, CDE)1, 2 offers the following guidelines for timing of bolus insulin, based on the glycemic index of the food, as well as the pre-meal glucose reading:
BG Above Target
30-45 mins before eating
20-30 min before eating
BG Within Target
BG Below Target
10-15 min after meal
From the chart we can see that the highest pre-bolus times are required when BG is high and fast-digesting foods are about to be eaten (these are high glycemic index (GI) foods like watermelon and soda crackers – see strategy #10 below). You can also see from the chart that you don’t need to pre-bolus ahead of time for a moderate GI meal if BG is on the lower end of target, or if the pre-meal BG is at target (4-8 mmol/L) and your child is about to eat slow-digesting (low glycemic index) foods like apples, pasta, legumes, and brown rice. And if BG is below target AND low GI foods are planned, then you may even need to bolus after your child has already started eating.
For more details on timing of meal insulin, see Gary Scheiner’s book Think Like a Pancreas, as well as his website, IntegratedDiabetes.com.
For more on glycemic index of foods, check out Jennie Brand Miller’s Glucose Revolution books, and
6. Tweak the Shape of Insulin Delivery
- low on the glycemic index
- high in fat
- low-carb (if they primarily consist of protein and/or fat)
- eaten over an extended period of time (for example, the grazing that often happens at birthday parties or picnics)
- very large portions (which digest at a different rate than smaller portions).
These pump features alter the rate and “shape” of either bolus or basal insulin delivery respectively, to better match how quickly sugar enters the bloodstream for different types of foods.
An extended bolus allows you to specify how much of the bolus insulin is delivered up front as a normal bolus, and how much is delivered over a specified period of time. For example, when my son eats pasta, we use a 50/50 extended bolus over 3 hours: this means that 50% of the insulin dose is given up front, and the remaining 50% is trickled in over the next 3 hours.
A temporary basal rate allows you to increase or decrease the amount of insulin given as basal (background insulin). After eating high-fat foods, increasing the insulin rate by 50-60% for 5-8 hours is not uncommon. For example, if your child eats a gooey, cheesy pizza, you could bolus for the carb content of the pizza, and then also set a temp basal rate increase of, say, 60% for 4 hours (which is referred to as a temp basal rate of 160% on some devices, where 100% is the normal bolus); this means that if the current basal rate is 1.0 U/hr, then for the next 4 hours basal insulin will be delivered at a rate of 1.6 U/hr, to cover the fat content of the pizza. And if the programmed basal rate changes during those 4 hours, then the temp basal rate would change correspondingly.
For details on how to use extended bolus and temp basal rates, check out other Waltzing the Dragon articles as linked above.
7. Borrow from Future Insulin
A “super bolus” is a method of super-charging the effectiveness of a normal insulin bolus, detailed by John Walsh, PA, CDTC (Certified Diabetes Technology Clinician), co-author of the Pumping Insulin books.
Using an insulin pump, you borrow from the basal insulin that is planned to be delivered over the next few hours (3 hours, for example), by setting a temp basal reduction for 3 hours just before the meal, and then give as an up-front bolus the amount of insulin that would have been delivered during that time. In this way, you deliver the same amount of insulin during that time period, but you deliver more of it upfront to tackle the post-meal BG spike. The super bolus is especially useful for certain foods which cause a large post-prandial peak of blood sugar (like many breakfast cereals), especially those that digest quickly and therefore quickly impact blood sugar.
For example, if your child’s basal rate at breakfast time is 0.8 units/hour, then you can bolus up to 2.4 units before breakfast if you suspend basal delivery for 3 hours. Alternately, you could bolus 1.2 units before breakfast and then reduce the basal rate to 50% of the programmed rate. How much insulin you borrow depends on factors like how high your pre-meal glucose is, how many carbs you are about to eat, and how quickly (or slowly) the food will digest.
For more details on the super bolus, check out John Walsh’s Pumping Insulin books, as well as his website DiabetesNet.com.
8. My Meal (Part 2): The Sequel
In order to avoid flooding the body with carbs, you could tame those spikes by delaying eating part of the food for which you have given insulin: you bolus now for the whole meal, but only eat part of it now, saving the rest to eat 1-2 hours later. To look at it from another angle, bolus now for the meal plus some extra insulin; you eat the meal as usual now, and then 1-2 hours later you cover the “extra” insulin with a snack.
For example, if your child’s morning insulin-to-carb ratio is 1:10 and she wants to have an 8am breakfast containing 40 grams of carbs, but her blood sugar before the meal is above target, to flatten the post-meal curve you could give 6 units of insulin before breakfast (which would cover 60g of carbs). Four of those units of insulin will be covered by breakfast (40g of carbs), leaving 2 units (or 20g of carbs) to be covered by a mid-morning snack at around 9:30 or 10:00am.
Of course, the one caveat with this strategy is that the snack CANNOT be missed, or low blood glucose is almost inevitable. It would be wise to set up a double (or triple) safe reminder.
9. Insulin Choice
The insulin program that your child is on can also affect post-meal spikes. A program using N/NPH gives the least amount of power over post-meal spikes, while intensive insulin therapy regimes allow you to pump up that power (Multiple Daily Injections (MDI) and, to an even greater degree, Insulin Pump Therapy).
Your choice of rapid-acting bolus insulin can also impact post-prandial blood sugar. Humalog, NovoRapid & Apidra all have pretty much the same insulin action: they start working in 15 mins and are strongest at around 60 mins. However, Fiasp nudges out the competition by starting to work about 6 minutes earlier, working 50% harder during the first 30 minutes, and coming on strongest ~7 minutes earlier4. Check with your child’s diabetes health care team to see if a change in insulin program or brand of bolus insulin would help to reduce post-meal blood glucose spikes.
These last several strategies have addressed some ways to use insulin to head off high blood glucose after meals. But we can also reduce post-meal spikes by trying some new approaches with food.
10. Try Tortoise Food
The relatively slow action of insulin, compared to the fast sugar-raising action of food, can sometimes seem like a classic tortoise and hare situation. To give the tortoise a fighting chance, try tortoise food (that is, food low on the Glycemic Index) to better match the relatively slow action of even the most rapid-acting insulins, which take 15 minutes just to start acting and about an hour to reach peak effectiveness, one food-based strategy involves choosing foods that digest more slowly. That is, foods that are lower on the Glycemic Index (GI).
More on the Glycemic Index, GI values and what they mean:Glycemic Index Explained
High GI foods are digested quickly. Their effect on blood glucose peaks in about 30-60 minutes.
Examples of high GI foods may incudle watermelon, wheat flour bread, gluten free white bread, Cheerios, soda crackers, pretzels, mashed potatoes, long grain white rice, Gatorade, jelly beans, instant oatmeal, and Cookies & Cream Clif Bar5.
Medium GI are digested at a moderate rate that perhaps best matches the insulin action of rapid-acting insulin (like Humalog, Novorapid, Apidra and Fiasp): their effect peaks in 60-90 minutes.
Some examples include bananas, cantaloupe, pineapple, sweet corn, pure honey, rice vermicelli, pita bread, home made pancakes, white basmati rice, and Chocolate Brownie Clif Bar5.
Low GI foods digest quite slowly, creating a modest rise in BG and taking 2 or more hours to peak.
Some examples include sourdough bread, pasta, quinoa, oatmeal made from rolled oats, chick peas, peanuts, oranges, apples, pears, green peas, plain chocolate, milk, plain yoghurt, and premium ice cream.
In general, slower-digesting, low-GI carbs tend to be:
- Whole foods, rather than processed
- whole grain crackers digest slower than soda crackers
- apples digest slower than apple cereal bar
- Higher in fibre
- brown rice will spike BG less than white rice
- sweet potatoes digest slower than white potatoes
- Contain some fat
- ice cream will give a flatter curve than a popsicle
- Solids, compared to the liquid form
- oranges will raise BG slower than orange juice
- Cold, compared to hot
- Cold potato salad digests slower than hot, mashed potatoes
- Raw or lightly cooked, rather than well- or over-cooked
- Al dente pasta is slower than mushy pasta
- Raw carrots raise BG slower than cooked carrots
- A meal that includes lemon juice or oil & vinegar (for example, as a dressing on a salad) will digest slower than one without.
- Whole foods, rather than processed
More on the Characteristics of Low GI Foods:What Makes a Food High or Low GI?
So how can we apply the glycemic index to address a problem with high blood glucose after eating? The Diabetes Canada 2018 Clinical Practice Guidelines state: “Replacing high-glycemic-index carbohydrates with low-glycemic-index carbohydrates in mixed meals has a clinically significant benefit for glycemic control in people with type 1 and type 2 diabetes.”6
Some ideas for a high-to-low-GI swap:
- Breakfast time: You could swap out instant oatmeal for regular rolled oats, try yoghurt + fresh fruit instead of wheat toast and jam, SpecialK instead of Cornflakes, a high-fibre cereal (like All-Bran) instead of Rice Krispies.
- Lunch time: How about a sandwich on whole grain or sourdough bread instead of white or whole wheat? Or a quinoa and chick pea salad with a lemon vinaigrette dressing?
- For a snack: Try whole grain crackers with cream cheese instead of plain soda crackers, an apple instead of watermelon, chia pudding and berries instead of cookies.
- Supper time: Try potato salad or sweet potato instead of regular mashed potatoes to smooth out those post-meal spikes. Go with al dente pasta rather than white buns; plan a meal around rice vermicelli or basmati rice rather than long grain white rice.
Other Glycemic Index Resources:
11. Bring on the fibre!
When reading a nutritional panel, have you ever wondered why we subtract the fibre amount from the carb amount, and then give insulin only for this “net carb” amount? It’s because of the mediating affect of fibre on glucose levels in the blood. Our bodies do not digest insoluble fibre (the “roughage” found in wheat bran, whole grains, celery and many fruit/vegetable skins); it simply travels through the digestive tract, sweeping up as it goes along. Since it doesn’t get digested, it doesn’t affect blood glucose. On the other hand, insoluble fibre (the gummy, sometimes gel-like material in oats, barley, strawberries and apples) is thought to change the structure of food in the stomach, which slows the rate at which starches are broken down as they are digested, and so helps to level out post-meal blood sugar. As a result, increasing your intake of dietary fibre may make an impact on the post-meal rise in blood glucose.
A statement from the Nutrition Therapy chapter of the 2018 Diabetes Canada Clinical Practice Guidelines6, though not specifically addressing the needs of children and teens with T1D, reads:
“The evidence supporting metabolic benefit is greatest for viscous soluble fibre from different plant sources (e.g. beta-glucan from oats and barley, mucilage from psyllium, … pectin from dietary pulses … and temperate climate fruits (apples, citrus fruits, berries, etc.) The addition of viscous soluble fibre has been shown to slow gastric emptying and delay the absorption of glucose in the small intestine, thereby improving postprandial glycemic control.” 8 (emphasis added)
It goes on to say:
“Despite contributing to stool bulking, insoluble fibre has failed to show similar metabolic advantages in randomized controlled trials in people with diabetes… (therefore) mixed sources of fibre may be the ideal strategy. Interventions emphasizing high intakes of dietary fibre (≥20 g/1,000 kcal per day) from a combination of types and sources with a third or more provided by viscous soluble fibre (10 to 20 g/day) have shown important advantages for postprandial BG control.” 6
You can get fibre naturally from plant food sources, such as:
- Fresh fruits and vegetables
- Beans, peas and lentils
- Whole-grain breads, cereals, pasta, and crackers
- Brown rice and other whole grains, such as oats, kasha, barley and quinoa
- Bran products
- Nuts and seeds
If you find it a challenge to get enough fibre from food sources, fibre supplements may help.
A 2016 study found that supplementing a diet with water soluble fiber from psyllium improved glycemic control for adults with type 2 diabetes: fasting blood glucose decreased from pre- to post-intervention measures (from 9.1 down to 6.6 mmol/L in the experimental group), as did HbA1c (from 8.5 down to 7.5 % in the experimental group). There was no change in either measure in the control group.7
Similarly, in a 2007 study 7 when adults with type 2 diabetes were given milk containing psyllium granules with breakfast, their pre-meal glucose readings rose an average of only 1 point at 1-hour post-meal (while the same measure was 3 mmol/L for the control group). At 2 hours post-meal, the difference was even greater: average postprandial plasma glucose was 6.5 mmol/L for the psyllium group, and 9.3 for the control.8
Though we cannot translate these research results directly to our T1D kids*, the concept is encouraging. Given that psyllium fibre is inexpensive and that the potential side effects would likely be temporary GI side effects,** this strategy may be worth trying out for our families.
(*The subjects in both studies were adults with type 2, and the sample size for the 2007 study was small.)
(**Bloating, gas, constipation or diarrhea, for example, which can be reduced by increasing fibre intake gradually and drinking plenty of water.)
12. Add Vinegar to The Meal
This may come as a surprise, but including highly acidic foods in a meal slows down stomach emptying, which slows down the glucose-raising effect of the whole meal and moderates blood sugar spiking.9,10 This is why eating a sandwich made of sour dough bread will flatten the curve more than one made with white bread, or even processed whole wheat bread, as sourdough contains lactic acid and propionic acid, natural by products of the fermentation process. To increase the acidity of your meal (and so reduce the rate at which it is digested) you could use oil and vinegar dressing on a salad, sprinkle salmon with lemon juice, or add a pickle or two to your sandwich plate.
Glycemic Index guru Jennie Brand-Miller and her co-authors report that a Salad dressing with 4 teaspoons of vinegar (or lemon juice) + 8 teaspoons of oil, consumed with a "mixed" meal, has significant blood glucose lowering effects (30 percent less blood sugar response to an average meal.) 9
13. Mix Your Macros
As an application of the glycemic index concept, you can moderate post-meal BG spikes by building meals that include a combination of macronutrients (carbs, protein, and fat). That is, instead of eating carbohydrates alone, adding protein and/or fat to your child’s meal or snack can smooth out the BG curve. For example, crackers alone will digest quicker (and raise BG faster) than crackers and cheese. Or crackers with peanut butter. Or crackers with sliced kielbasa. Layer toast with mashed avocado and hemp seeds. Add a handful of peanuts to that summer-day watermelon-fest. (Peanuts can be particularly handy, as they deliver a good dose of both protein and fat.)
How much fat or protein is enough? How much is too much? Well, that’s not an exact science. But one 2001 study of the influence of dietary fat on postprandial glucose metabolism 11 may give us a clue. They found that for a small sample of non-diabetic women, a Moderate Fat meal lead to a flatter post-meal glucose curve than a Low Fat meal, while also producing the flattest curve without creating a major secondary blood sugar spike due to insulin resistance (like the High Fat meal had done).
In their test meals they fixed the amount of carbs and protein from pasta at 63g and 13g respectively, then varied the fat content of the meal:
- the Low Fat meal contained less than 2g of fat, the equivalent of one-third of a teaspoon of sunflower oil (resulting in a fat:carb ratio of 2.5:100);
- the Moderate Fat meal contained almost 17g of fat, the equivalent of ~ 3 1/2 tsp of sunflower oil (Fat: carb = 26:100), and
- the High Fat meal contained over 41g of fat, the equivalent of 3 tbsp of sunflower oil (fat:carb = 66:100).
The Moderate Fat meal stopped the spike and lead to only a small secondary rise in glucose at 3 hours after eating; the High Fat meal also suppressed the post-meal spike, but lead to a large secondary glucose rise at 5 hours after eating; the Low Fat meal, though not leading to a secondary rise in BG, also did not have enough fat to alter the post-meal spike, as so spiked higher than either of the other two. Though once again we cannot directly apply these results to our T1D kids and teens, the concept is worth trying out as we build snacks and meals at home which will dampen post-meal BG spikes.
14. Go Low-Carb While You Wait
We don’t generally avoid carbohydrates in our family, but when our son wants a snack and his glucose is already above-range, a low-carb or carb-free snack may be necessary to prevent an escalating BG spike, and to give it a chance to return to target. For example, let’s say his glucose is 13.0 mmol/L when he’s ready to have a snack… a pre-bolus won’t bring this down to target within 15 or even 30 minutes, so if he eats carb-containing food at an elevated pre-meal BG, it will rise the usual 4-6 points, now to around 18, and will take even longer to return to range. So instead, when BG is above 10, our son can choose* to have a very low carb snack, such as cheese, eggs, nuts, cucumber, snap peas, seaweed snacks, or turkey-cheese-pickle rolls. We have found this approach particularly helpful if there is only 1-2 hours until the next meal (that is, there’s more limited time to get things back on track).
In creating this article, I leaned on the work of some T1D greats: Gary Scheiner (whom I heard speak at Friends for Life Conference several years ago, and whose book Think Like a Pancreas should be required reading for dragon tamers) and John Walsh (whose books on Pumping Insulin have equipped our family to get the most from our tech, and whom I also heard speak at a Friends for Life Conference), as well as Glycemic Index guru Jennie Brand-Miller (whose Glucose Revolution books, recipes and GI list from The University of Sydney have helped us to get a grip on food-related BG swings).
I thank these individuals not just for the impact they have had on this article and will have on all the WTD readers who benefit from it, but most especially for the impact they had on our family’s dragon taming experience. We couldn’t have done it without you!
Notes & References:
- Gary Scheiner, (2010) Strike the Spike, New and Improved. https://integrateddiabetes.com/Articles/gen/Strike%20The%20Spike%202.pdf
- Gary Scheiner, (2019) Strike the Spike: Controlling Blood Sugars After Eating https://tcoyd.org/2019/10/strike-the-spike-controlling-blood-sugars-after-eating/
- Slattery, D., Amiel, S. A., & Choudhary, P. (2018). Optimal prandial timing of bolus insulin in diabetes management: a review. Diabetic medicine : a journal of the British Diabetic Association, 35(3), 306–316. https://doi.org/10.1111/dme.13525
- Gary Scheiner, (2017) Review of FiASP insulin and how it compares with other fast insulins https://integrateddiabetes.com/review-of-fiasp-insulin-and-how-it-compares-with-other-fast-insulins/
- GlycemicIndex.com, Glycemic Index list
- Sievenpiper J, Chan C, Dworatzek P, et al. Diabetes Canada 2018 Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada: Nutrition Therapy. Can J Diabetes 2018;42(Suppl 1):S67.
- Abutair, A. S., Naser, I. A., & Hamed, A. T. (2016). Soluble fibers from psyllium improve glycemic response and body weight among diabetes type 2 patients (randomized control trial). Nutrition journal, 15(1), 86. https://doi.org/10.1186/s12937-016-0207-4
- Siavash, M., Salehioun, M., Najafian, A., & Amini, M. (2007). A randomized controlled study for evaluation of psyllium effects on kinetics of carbohydrate absorption. Journal Of Research In Medical Sciences, 12(3), 125-130. Retrieved from http://jrms.mui.ac.ir/index.php/jrms/article/view/576/356
- Brand-Miller, J, K Foster-Powell and R Mendosa. 2003. What Makes My Blood Glucose Go Up... and Down? And 101 Other Frequently Asked Questions About Your Blood Glucose Levels. New York: Marlowe & Co.
- Ostman, E, Y Granfeldt, L Persson and I Bjorck. 2005. Vinegar supplementation lowers glucose and insulin responses and increases satiety after a bread meal in healthy subjects. European Journal of Clinical Nutrition 59(9):983-8.
- Normand, Sylvie, Yadh Khalfallah, Corrine Louche-Pelissier, Christiane Pachiaudi, Jean-michel Antoine, Stephane Blanc, Michel Desage, Jean Paul Riou and Martine Laville. 2001. Influence of dietary fat on postprandial glucose metabolism (exogenous and endogenous) using intrinsically 13c-enriched durum wheat. British Journal of Nutrition 86: 3-11.
This material has been developed from sources that we believe are accurate, however, as the field of medicine (in particular as it applies to diabetes) is rapidly evolving, the information should not be relied upon, as it is designed for informational purposes only. It should not be used in place of medical advice, instruction and/or treatment. If you have specific questions, please consult your doctor or appropriate health care professional.
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