Peanut butter is a popular spread and a component of one of the most iconic sandwiches in the United States. Rich and creamy, it can increase the protein content of many snacks and meals. When homemade, peanut butter is an unprocessed food, as the peanuts are often roasted, ground, and turned into a paste. However, commercial peanut butter companies add in sugar, oils, and trans fats, which influence the glycemic index and health benefits of this delicious nut butter.
This article will explore how peanut butter may impact blood sugar levels and the health benefits of including this spread in your diet.
Peanuts are considered a low glycemic index food with a rating of 13.¹ Peanuts contain carbohydrates, yet they also contain important nutrients like fiber, which ensures that when eating this food, the body will digest it slowly and release sugar gradually into the bloodstream, allowing you to avoid rapid, steep blood sugar spikes.
Peanut butter, in itself, does not have an individual glycemic index rating since, in its purest form, it is created by roasting peanuts. This cooking method does not alter the glycemic index of the nut. The peanuts are then ground into a paste, which consumers know as peanut butter.
Added ingredients in commercially available peanut butter products do impact the glycemic index of this nut butter. Be mindful to check the nutritional labels of products to identify what other ingredients are present in your peanut butter.
The below glycemic index and glycemic load data is for 100g of raw peanuts, which is approximately two-thirds a cup:¹ ²
Peanut butter is a balanced energy source that contains all three major macronutrients: carbohydrates, protein, and fat. It contains only 20% carbs, making it perfect for a low-carb diet, but it is extremely high in fats, which contributes to a high-calorie count.
The nutritional information below is for 100g of raw peanuts.²
B6 (0.44 mg), Calcium (49 mg), Magnesium (180 mg), Phosphorus (380 mg), Potassium (636 mg)
While being high in fat and calories, peanuts do not appear to actively contribute to weight gain.²³ Observational studies have shown that consuming peanuts may help maintain a healthy weight and reduce the risk of obesity.²⁴ ²⁵ ²⁶ ²⁷
One small study with healthy women suggested that when other sources of fat were replaced with peanuts, the participants lost 6.6 pounds.²⁸ Another study found that when three ounces of peanuts were added to the daily diet of healthy adults for eight weeks, they did not gain as much weight as expected.²⁹
However, while peanuts may help with weight loss goals, peanut butter often contains added sugar and other ingredients that may work against these efforts. Check the ingredients list of all peanut butter products before purchasing and try to buy natural peanut butter, when possible.
Peanut butters without added sugar or other ingredients have a low glycemic index rating and are a great choice for those living with diabetes. However, peanut butter is rarely eaten alone, and is often paired with carbs like oatmeal, toast, or apples. When paired with these types of carbohydrates, the fat and protein in peanut butter slows down the digestion of the carbohydrates, leading to a smaller blood sugar spike.
However, not all peanut butter brands are created equal. Be mindful of added ingredients to peanut butter products and look for natural varieties made without hydrogenated oils (trans fats).
Peanuts also contain high levels of omega-6 fatty acids, which tend to increase inflammation. A high intake of omega 6 may cause imbalances in the ratio of healthy fatty acids and increase the risk of obesity and insulin resistance.²² To reduce this imbalance, be mindful of serving sizes when consuming peanut butter.
While peanuts are associated with many health benefits, there are some health concerns to consider.
Peanuts are one of the most common food allergens in the world, and approximately 1% of Americans possess this allergy.¹⁷ Peanut allergies are potentially life-threatening and are sometimes considered to be the most severe allergen.¹⁸ Symptoms of a peanut allergy include itchiness of the mouth, lips, or throat, swelling, and redness. In severe cases, allergic reactions can cause hives, difficulty breathing, and anaphylaxis. Please consult a healthcare professional if you suspect an allergy, sensitivity, or intolerance to peanuts.
Peanuts can also be contaminated with Aspergillus flavus, a mold that produces aflatoxin. Aflatoxin poisoning can cause a loss of appetite, yellow discoloration of the eyes (jaundice), liver failure, and liver cancer.¹⁹
Fortunately, when processing peanuts into peanut butter, the preparation method can significantly reduce the amount of aflatoxins in the final product.²⁰ Additionally, the United States Department of Agriculture (USDA) closely monitors the amounts of aflatoxins in foods. If your purchase peanut butter or peanuts that appears moldy, shriveled, or discolored, you should discard it immediately.²¹
The glycemic index (GI) is a measure of how quickly a carbohydrate-containing food raises blood sugar levels compared to a reference food, usually glucose. It ranks foods on a scale from 0 to 100, with higher values indicating a faster rise in blood sugar. The glycemic index (GI) scale is typically categorized as follows: Low GI [55 or less], Medium GI [56-69], High GI [70 or higher]. Foods with a high glycemic index digest rapidly and can cause dramatic fluctuations in blood glucose or glucose spikes.
Glycemic load (GL) takes into account both the quality (glycemic index) and quantity (carbohydrate content) of carbohydrates in a specific serving of food. It is a measure of how much a particular food will raise blood sugar levels. GL is calculated by multiplying the glycemic index of a food by its carbohydrate content and dividing it by 100. It provides a more accurate representation of the overall impact of a food on blood sugar compared to the glycemic index alone.
Yes, peanut butter can spike insulin levels. Peanut butter contains carbohydrates and protein, both of which can cause an increase in insulin secretion. However, the extent of the spike in insulin levels will depend on the amount of peanut butter consumed and the individual's insulin sensitivity. It is important to consume peanut butter in moderation and pair it with other foods that can help regulate blood sugar levels.
Peanut butter has a low glycemic index due to its high fat and protein content, which slows down the absorption of carbohydrates. However, the glycemic index can vary depending on the brand and type of peanut butter. It is important to check the label for added sugars and choose natural peanut butter without added sugars.
Yes, people living with diabetes can eat peanut butter in moderation as it is a good source of protein and healthy fats. However, it is important to choose natural peanut butter without added sugars and to monitor portion sizes to avoid consuming too many calories.