Is Custard High GI? Understanding its Glycemic Index

November 10, 2025 •

4 min read

According to the Blue Circle Diabetes Foundation, a 100g serving of prepared custard has a low glycemic index (GI) of 35. The seemingly simple question, "Is custard high GI?" has a surprisingly nuanced answer that depends heavily on its ingredients and how it's prepared.

Quick Summary

The glycemic index of custard varies depending on its preparation, with store-bought versions often being high in sugar. Homemade custard, particularly when made with low-fat milk and sugar substitutes, typically falls into the low GI category, making it a manageable option for blood sugar levels.

Key Points

Low GI for Basic Custard: Simple, prepared custard typically has a low glycemic index of around 35.
Ingredients Determine GI: The glycemic impact of custard depends heavily on its ingredients, especially the amount and type of sugar used.
Homemade vs. Commercial: Homemade custard with sugar substitutes and low-fat milk is a better low-GI option compared to processed, sugary commercial versions.
Protein and Fat Buffer GI: The protein from eggs and milk fat in custard slow down sugar absorption, mitigating blood sugar spikes.
Portion Control is Key: Even low-GI versions should be consumed in moderation to effectively manage blood sugar.
Customization for Health: Modify your custard recipe by using low-carb milk alternatives and natural sweeteners for a more diabetes-friendly dessert.

Understanding the Glycemic Index

The glycemic index (GI) is a ranking system for carbohydrate-containing foods based on how they affect blood glucose levels. Foods are categorized as low (55 or less), medium (56-69), or high (70 or more) GI. The GI of a food is influenced by several factors, including its type of sugar, preparation method, and the presence of fat, fiber, and protein.

The Surprising Truth About Custard's GI

The question "is custard high GI?" is not a simple yes or no. The GI of custard can change dramatically depending on how it is made. Prepared custard made from a simple custard powder mix, milk, and eggs can have a surprisingly low GI, sometimes as low as 35. This is because the overall glycemic response is buffered by the fat and protein from the milk and eggs, which slow down digestion and the release of glucose into the bloodstream.

However, commercially produced or heavily sweetened custards are a different story. These often contain high amounts of added sugar and other high-GI ingredients that can cause a rapid spike in blood sugar. The inclusion of fruits, which contain their own natural sugars, can also increase the total glycemic load of the dessert.

Factors Affecting Custard's Glycemic Impact

Several factors play a crucial role in determining whether custard is a high or low-GI food:

Added Sugars: The most significant factor. Excessive added sugar, like sucrose, can drastically increase the GI. Homemade versions allow for the use of low-calorie or non-nutritive sweeteners.
Type of Milk: The type of milk used can influence the GI. Dairy milk contains lactose, which contributes to the carbohydrate content. Using low-fat or plant-based milks, such as almond milk, can reduce the carbohydrate load.
Fat and Protein Content: The fat from milk and the protein from eggs help to slow down the digestive process. This slower digestion rate prevents rapid spikes in blood sugar, contributing to a lower GI.
Additional Ingredients: What you add to your custard makes a huge difference. Serving custard with high-fiber ingredients like nuts and seeds or low-sugar berries will further lower its overall glycemic impact. Conversely, pairing it with high-GI accompaniments like sugary canned fruits will have the opposite effect.
Processing: The degree of processing also matters. Highly processed, ready-made custards or fillings often contain more sugar and refined starches, pushing them into the medium-to-high GI range.

Low-GI Custard vs. High-GI Custard

Here is a comparison demonstrating how different preparation methods can alter custard's glycemic profile.


Feature	Low-GI Custard	High-GI Custard
Preparation	Homemade, with careful ingredient selection.	Commercially prepared or heavily sweetened.
Sweetener	Low-calorie or natural sugar substitutes like stevia, monk fruit, or xylitol.	Refined white sugar, high-fructose corn syrup, or fruit juice concentrate.
Milk Type	Low-fat milk, almond milk, or other plant-based alternatives.	Full-fat milk or cream, especially in large quantities.
Additional Ingredients	Paired with fresh berries, nuts, or seeds for added fiber and protein.	Served with sugary syrup, canned fruit in heavy syrup, or high-sugar pastries.
GI Range	Typically low (under 55).	Can be medium to high, causing blood sugar spikes.

How to Make a Diabetes-Friendly Custard

Creating a delicious custard that won't cause a blood sugar spike is easy with the right approach. Here are some steps you can follow:

Choose the right milk: Opt for low-fat dairy milk, almond milk, or soy milk. Almond milk is particularly low in carbohydrates.
Use sugar substitutes: Replace refined sugar with natural sweeteners like stevia, erythritol, or monk fruit. These provide sweetness without the glycemic impact.
Boost protein: Increase the protein content by using skimmed milk powder or adding extra egg whites. Protein helps slow down sugar absorption.
Incorporate healthy fats: While fat content influences GI, it's the type of fat that matters most. Using healthy fats like those from nuts or coconut oil can further slow down digestion.
Serve with fiber: Pair your custard with fresh, low-sugar fruits like berries, which add fiber and nutrients, slowing digestion even more.
Control portion sizes: Even a low-GI food can raise blood sugar if consumed in large quantities. Practicing portion control is key for managing blood sugar levels effectively.

Conclusion

So, is custard high GI? The answer is no, not inherently. While heavily processed, high-sugar versions can be, homemade custard prepared with low-fat milk and sugar substitutes typically has a low GI profile. The fat and protein from the milk and eggs slow digestion, making it a manageable dessert for those monitoring blood sugar. By being mindful of your ingredients and portion sizes, you can enjoy a delicious, creamy custard without the blood sugar rollercoaster. For those with specific dietary concerns, consulting a healthcare provider or dietitian is always recommended before making significant changes to your diet. For more information on food factors and gastrointestinal function, a comprehensive article can be found on PubMed.

Frequently Asked Questions

Yes, many store-bought or commercially prepared custards contain high amounts of added sugar, which can significantly increase their glycemic index and cause a rapid rise in blood sugar levels.

Yes, diabetics can eat custard, but it is crucial to consume it in moderation and choose a version with low sugar content. Opt for homemade versions using sugar substitutes and low-fat milk to better manage blood sugar.

For a low-GI custard, consider using low-fat dairy milk, almond milk, or soy milk. Almond milk is a popular choice for its low carbohydrate content.

To lower the GI of homemade custard, use sugar substitutes like stevia or erythritol instead of refined sugar, incorporate healthy fats from nuts, and serve it with high-fiber fruits like berries.

Yes, adding fruit to custard can affect its glycemic load due to the natural fruit sugars (fructose). To minimize the impact, choose fruits with lower sugar content, such as berries, rather than high-sugar canned fruits.

Custard powder alone, which is mostly cornstarch, has a low GI. Its overall effect on blood sugar depends entirely on what it is mixed with, primarily the milk and sugar.

For low-GI alternatives, consider options like chia seed pudding, yogurt with no added sugars, or homemade recipes using ingredients like almond milk and natural sweeteners.