Is Reese’s crunchy king size Keto?

The Ingredient Breakdown

As a food scientist, looking at the label for Reese’s crunchy king size reveals a formulation designed for sweetness and texture, not metabolic health. The primary issue for keto dieters is the sheer volume of high-glycemic carbohydrates. The very first ingredients listed are peanuts and sugar, establishing immediately that this is a sugar-forward product.

Beyond plain sugar, the bar utilizes corn syrup solids and high fructose corn syrup. These are potent sweeteners that are rapidly absorbed into the bloodstream. For a keto diet, which generally limits total carbohydrates to under 20-50 grams per day, the amount in a single king size bar is prohibitive. Additionally, the presence of dextrose—a form of glucose—adds to the total carb count significantly.

We also see rice flour listed. This is a refined grain starch. While it provides the 'crunchy' texture in the name, it contributes pure carbohydrates without fiber to offset the impact on blood sugar. Finally, the inclusion of hydrogenated vegetable oils (palm kernel, soybean) and mono- and diglycerides are emulsifiers used to give the candy its smooth mouthfeel and shelf stability, but they offer no nutritional value and are often processed fats.

Nutritional Value

From a nutritional standpoint, a king size Reese’s crunchy bar is essentially a calorie bomb composed almost entirely of sugar and fat. A standard king size package contains two bars, and the carbohydrate count is substantial—often exceeding 50 grams of total carbohydrates per package with very little dietary fiber to mitigate the impact. This results in a 'net carb' count that is far too high for ketosis.

The fat content is high, but it comes paired with these sugars, creating a combination that is likely to trigger insulin spikes. While the peanuts and dairy butter do provide some protein and fat, they are drowned out by the sugar and corn syrup. For anyone tracking macronutrients, this item would consume almost your entire daily carbohydrate allowance in just one snack, leaving no room for nutrient-dense vegetables or other necessary foods.