Does Peanut Butter Spike Your Blood Sugar?

TL;DR: Peanut butter barely affects blood sugar. With a glycemic index of just 14, it is one of the lowest-GI foods available. A 2-tablespoon serving contains only 6 grams of carbohydrate, 7 grams of protein, and 16 grams of fat. The high fat and protein content actually slows the absorption of carbohydrates from other foods — peanut butter on toast reduces the toast’s glucose spike by 20–30%.

Does peanut butter spike blood sugar?

No. Peanut butter has a glycemic index of 14, which is extremely low. A standard 2-tablespoon (32 g) serving contains approximately:

• 6 grams of carbohydrate (of which 2 g is fiber)
• 7 grams of protein
• 16 grams of fat

The net carbohydrate content of 4 grams produces a negligible blood glucose response. The dominant macronutrients — fat and protein — do not raise blood sugar directly and actually slow the digestion of any carbohydrates eaten alongside.

Peanut butter produces essentially no measurable glucose spike when eaten alone. A 2018 study in the British Journal of Nutrition found that adding peanuts to a high-GI meal reduced the overall glycemic response by approximately 30 percent.

Nut butters compared: blood sugar impact

Nut butter	Glycemic index	Carbs per 2 tbsp	Fat per 2 tbsp	Protein per 2 tbsp
Peanut butter (natural)	14 (very low)	6 g	16 g	7 g
Almond butter	~15 (very low)	6 g	18 g	7 g
Cashew butter	~22 (low)	9 g	14 g	6 g
Sunflower seed butter	~18 (very low)	7 g	16 g	7 g
Nutella	~33 (low–medium)	22 g	11 g	3 g

Nutella stands out because it is primarily sugar and palm oil with a small amount of hazelnuts. At 22 grams of carbohydrate per serving (mostly sugar), Nutella has nearly 4 times the carbs of natural peanut butter and is fundamentally a different product from a blood sugar perspective.

All natural nut butters (peanut, almond, cashew, sunflower) have very low glycemic indices and are effective at blunting glucose spikes from other foods.

Why does peanut butter reduce blood sugar spikes from other foods?

When peanut butter is eaten with high-GI foods like bread, crackers, or fruit, it reduces the overall glucose spike through three mechanisms:

1. Fat slows gastric emptying. The 16 grams of fat per serving significantly delays how quickly food leaves the stomach, spreading carbohydrate absorption over a longer period.
2. Protein triggers incretin hormones. Peanut protein stimulates GLP-1 and GIP, which enhance insulin secretion and slow gastric emptying.
3. Fiber adds viscosity. The 2 grams of fiber per serving contribute to a more viscous chyme in the intestine, slowing glucose absorption at the intestinal wall.

This is why peanut butter on toast produces a markedly smaller spike than toast alone. The bread’s glucose is released more slowly because the fat and protein from the peanut butter are slowing the entire digestive process.

Does the type of peanut butter matter for blood sugar?

Yes. Natural peanut butter (ingredients: peanuts, salt) and commercial peanut butter (ingredients: peanuts, sugar, hydrogenated oils, salt) differ meaningfully:

• Natural peanut butter: ~1 g sugar per serving
• Commercial peanut butter (Jif, Skippy): ~3 g added sugar per serving

The 2-gram difference per serving is small, but commercial peanut butters also contain hydrogenated vegetable oils that replace some of the healthier peanut oil. For blood sugar, the difference is minor — both are very low-GI. But natural peanut butter is the cleaner choice.

Reduced-fat peanut butter is actually worse for blood sugar. Manufacturers remove fat (which slows glucose absorption) and often add more sugar to compensate for flavor. The result is higher carbs and less of the fat that makes peanut butter blood-sugar-friendly.

What is the best way to use peanut butter for blood sugar management?

1. Spread it on high-GI foods. Peanut butter on bread, crackers, or rice cakes significantly reduces the spike from these foods.
2. Eat it with fruit. Apple slices or banana with peanut butter spike far less than the fruit alone.
3. Choose natural over reduced-fat. The fat is the mechanism that slows glucose absorption.
4. Use it as a pre-meal snack. A tablespoon of peanut butter 10–15 minutes before a carb-heavy meal primes GLP-1 release.
5. Add it to oatmeal. Peanut butter stirred into oatmeal reduces the oatmeal’s glycemic response by 20–30%.
6. Stick to 2 tablespoons. While peanut butter is blood-sugar-friendly, it is calorie-dense at 190 calories per serving.

Key takeaways

• Peanut butter (GI 14) is one of the lowest-glycemic common foods and produces essentially no blood sugar spike.
• A 2-tablespoon serving has only 4 grams of net carbs but 16 grams of fat and 7 grams of protein.
• Adding peanut butter to high-GI foods reduces their glucose spike by 20–30%.
• Natural peanut butter is slightly better than commercial varieties, which contain added sugar.
• Reduced-fat peanut butter is worse for blood sugar — less fat means less gastric emptying delay.
• Nutella has 4 times the carbs of natural peanut butter and is primarily sugar and oil.
• All natural nut butters (almond, cashew, sunflower) have similarly low glycemic indices.

Sources

• Foster-Powell, K., Holt, S.H., & Brand-Miller, J.C. (2002). International table of glycemic index and glycemic load values. American Journal of Clinical Nutrition, 76(1), 5–56.
• Viguiliouk, E., et al. (2014). Effect of tree nuts on glycemic control in diabetes: a systematic review and meta-analysis of randomized controlled trials. PLoS ONE, 9(7), e103376.
• Reis, C.E.G., et al. (2013). Acute and second-meal effects of peanuts on glycaemic response and appetite in obese women with high type 2 diabetes risk. British Journal of Nutrition, 109(11), 2015–2023.
• Kirkmeyer, S.V., & Mattes, R.D. (2000). Effects of food attributes on hunger and food intake. International Journal of Obesity, 24(9), 1167–1175.