Fat and protein bolusing for people with type 1 diabetes using pump therapy

This leaflet is for adults using insulin pump therapy to prevent high glucose levels following a high protein and/or fat meal.

The following are reasons why glucose levels can be higher for longer after eating carbohydrate as part of a high protein / fat meal:

• Digestion and absorption of carbohydrates (carbs) in a high fat/protein meal slows down and so continues like this for several hours longer
• High fat meals can cause short term insulin resistance so your usual dose of insulin for the carbohydrate is not as effective
• Excess protein from high protein meals is converted into glucose causing a delayed rise in glucose (typically 3-5 hours later)

Prior to using the information in this leaflet, please consider the following:

• Is your carbohydrate counting accurate? If you are not confident with this, please contact your diabetes educator for further discussion. It is unsafe for those who do not accurately carbohydrate count to use the information in this leaflet.
• Are your basal rates correct? For example do your glucose levels stay relatively steady over a 24 hour period if no carbohydrates are eaten / carb free meal? Please consult your educator for advice on basal testing if you are concerned about your basal rates.
• Are your carbohydrate ratios correct? For example do your glucose levels return to pre meal levels by 3-4 hours after your meal?
• This advice is not intended for those using hybrid closed loop systems such as Medtronic 780G Smartguard; CAM APS FX; Tandem T:slim control IQ*.

*note that you can use an extended bolus with the Tandem T:Slim; you can extend a bolus for up to 2 hours. The advice in this leaflet has not been tested in those using a hybrid closed loop system. If you choose to trial fat/protein bolusing with a Tandem T:Slim you may wish to speak to your diabetes educator first.

Should you require any support with your basal rates/carb ratios, consider basal testing and carbohydrate ratio testing. This information can be found in your pump DAFNE online modules (if you have completed pump DAFNE) or the CUH pump handbook. If you need specific support with this, do not hesitate to contact your diabetes educator.

If you are confident that your basal rates and carbohydrate ratios are correct, but you have identified that certain meals/foods regularly result in higher than expected glucose levels, you might want to consider giving your insulin differently; adding additional insulin and / or using different bolus options.

Bolusing for meals high in fat and/or protein with carbs

The effect of protein or fat on glucose levels can be different depending on whether the meal includes carbs or not. Let’s first look at bolusing for meals which are high in fat and/or protein which also contain carbohydrates.

Examples of problematic meals:

• fish and chips
• pie, creamy mash and vegetables
• cheese baguette, crisps and bar of chocolate
• curry, rice and naan
• fast food/fatty takeaways

There are three things to decide when bolusing for high fat/protein meals containing carbs.

1. How much extra insulin you need for the meal
2. How to split the bolus. That is how much of the bolus dose is given at the beginning and how much is given over an extended time.
3. How many hours/minutes over which the bolus needs to be extended over.

Below is an example of how to work this out and where is a good place to start. From your experience and the glucose patterns you see using a dual bolus and an add-on fat/protein bolus. It is likely that you will need to adjust this:

• calculate your bolus dose as usual
• add on 20% to this bolus dose.
• for example if you are eating 60g carbs, enter 72g (60+12) into the pump.
• select a dual bolus with 60%:40% (60/40) split
• set the duration of the dual bolus to 2½ hours (150 minutes).
• 60% of the bolus will be given immediately and 40% will be given over 2.5 hours (150 minutes)

Whenever possible, bolus for the meal 15 minutes before eating. If this is not possible and your glucose is above target before the meal, give a normal bolus correction 15 minutes pre-meal and bolus for the meal when it arrives.

How much extra insulin you need for the meal

Research suggests to start by adding an extra 20% to the bolus you have calculated for the carbs in your meal.

You may need a larger percentage increase for meals with higher than 100g carbohydrate; e.g. 25-35% increase.

Focus on getting the add-on bolus dose right before adjusting the split or bolus extension. If you have sensors, you can use this by checking your post meal glucose profile to help decide how effective your add-on bolus has been; as well as the split/extension. If you do not have a sensor, you will need to do fingerprick glucose testing at 3 and 5 hours to assess the efficacy; or to be extra sure, you can opt to check a blood glucose hourly for 5-6 hours.

The split of the bolus

A dual bolus can give some of the bolus straight away and some of the bolus over an extended period of time.

Research suggests to begin with a 60%:40% (60/40) split, although this is a starting point and may not necessarily work for you.

When you have eaten a particular food two or three times, review your patterns in glucose levels when you eat that particular food. For example, if you see a pattern where your glucose is above target after 3 hours, you may need more of the bolus at the start of the meal; try a 70%:30% (70/30) split with that meal next time. If you are using a sensor, consider what patterns you can see.

If you notice hypoglycaemia within 60 minutes of eating a meal, you may need less insulin pre meal; in this instance try a 50%:50% (50/50) split.

Different terms for dual bolus

• Medtronic pump “dual wave”
• Please note your Medtronic pump may not allow you to deliver a dual wave if your glucose level is above target; in this instance, you will need to do a standard bolus but be cautious with your add-on bolus.
• Tandem T:slim “extended”
• Omnipod DASH “extended bolus”
• YpsoPump “combination bolus”
• Medtrum “combo bolus”
• Dana “dual pattern bolus”

Bolus extension: how many hours the bolus needs to be extended for

The number of hours the bolus needs to be extended for can depend on a number of factors.

High fat meals are digested more slowly, causing a lower rise initially but then staying higher for longer beyond the time the bolus insulin is working. If this is the pattern you see you may need to extend the time.

Another reason for above-target glucose here is that, while digesting fatty meals, the body becomes more insulin resistant. The insulin resistance will contribute to the glucose staying higher for longer needing more insulin over a longer period of time.

A safe place to start is to extend the bolus over 3 hours. This means that some of the bolus will be delivered over a 3 hour period. If your glucose level is still above target 5 hours after the meal, you may need to extend the bolus for longer than 3 hours. If this is the case, try extending the bolus for 4 hours or more, depending on glucose checks.

Additional points

Repeat the meal, bolus settings and glucose checks at 3 and 5 hours after the meal at least twice to see what your glucose pattern is before making any changes.

There may be long gaps between eating the same meal, so it can be helpful to write down what you have done to refer back to the next time you have the meal, for example you may only have fish and chips only once every few months.

Most people find that working out an add-on fat/protein bolus can take far longer than achieving accurate bolus doses for carbs, so try to be patient.

Be cautious with add-on fat/protein boluses with bolus doses that are larger than normal for you. Larger bolus doses can work for longer than expected.

If you are drinking alcohol with or after the meal, or exercising after the meal, it may be safer not to use an add-on fat/protein bolus and wait to see a pattern.

What is classed as high protein?

The effect of protein on glucose levels is very individual. A general guide is that more than 40g of protein in a food or meal is classed as high protein. Here are some examples of food portions that contain around 40g of protein, or more.

What is classed as high fat?

The effect of fat on glucose levels is very individual. A general guide is that more than 30g of fat in a food or meal is classed as high fat. The fat may be in the starter, the main course, sides, snacks or desserts. A meal with more than one course is more likely to be high in fat. Here are some examples of food portions that contain around 30g of fat, or more.

Example of a meal high in fat/protein

Kebab: you calculate your meal has 80g carbohydrates, 65g protein and 40g of fat.

If you use a 1:10g ratio for your carbohydrates and have noticed your blood glucose levels always stay high after a kebab, we would recommend increasing your total insulin by 20% for this meal as the fat and protein are high

• You are eating 80g carbohydrate
• 20% allowance for the fat & protein in the kebab = 96g carbohydrate
• You would enter 96g carbohydrate into the pump
• Select a dual bolus with 60%:40% (60/40) split
• Set the time of the dual bolus to 3 hours.

If you remain above target by 3-4 hours after the kebab, then you may try a 30% increase in your carbohydrate value instead (up to 40%).

High protein meals containing no carbohydrate

We would suggest entering 10-15g carbohydrate (into your pump’s bolus calculator) for approximately 50g protein. This is equivalent to 1g carbohydrate for every 5g protein.

Only do this when the meal contains more than 50g protein.

For example: if your meal contains 65g protein; bolus for 13g carbohydrate (65÷5=13).

Start conservatively and only increase the insulin if you see a pattern of hyperglycaemia following high protein low/no carbohydrate meals.

Consider an extended bolus, rather than normal, (over 1-3 hours) due to the delayed effect of protein on glucose levels.

NB to deliver a square/extended bolus on a T:Slim, select “extended bolus”; set deliver now: 0%; deliver later: 100%.

Information within this patient information leaflet is based on OzDAFNE

Images: carbs and cals