How fattening is key lime pie?

Key lime pie is an American dessert consisting of key lime juice, egg yolks, and sweetened condensed milk in a pie crust. With its rich custard filling and tart lime flavor, key lime pie is considered a classic Southern and Floridian dessert. But with its high sugar and fat content, key lime pie is also quite caloric and fattening compared to other desserts.

Calories in Key Lime Pie

The main factors that contribute to the high calorie count of key lime pie are:

  • Pie crust – Standard pie crust is made from refined wheat flour and solid fats like butter or shortening. A 1/8 slice of a 9-inch single pie crust can provide 120-150 calories.
  • Sweetened condensed milk – This milk product is concentrated with added sugar, providing high amounts of calories and carbohydrates. A 1/4 cup of sweetened condensed milk has 220 calories.
  • Eggs – Egg yolks used in the custard filling are high in fat and cholesterol, with roughly 60 calories per yolk.
  • Added sugars – Key lime pie filling often contains additional granulated white sugar for enhanced sweetness. One tablespoon of sugar has 45 calories.

Considering all these high-calorie ingredients, one slice of key lime pie can easily provide 400-600 calories depending on exact serving size and recipe. For comparison, other popular desserts like apple pie, cheesecake, and chocolate cake typically range from 300-500 calories per slice.

Fat Content

In addition to high calorie content, key lime pie is very high in fat, especially saturated fat. Some of the main sources of fat in key lime pie include:

  • Butter/shortening in pie crust – These solid fats provide at least 110 calories and 12 grams of fat (7 grams saturated) per serving.
  • Sweetened condensed milk – Made by removing water from milk, sweetened condensed milk is very concentrated in fat and provides 9 grams of fat (5 grams saturated) per 1/4 cup serving.
  • Egg yolks – The yolky portion of eggs contains about 5 grams of fat each, over half of which is saturated.

With all of these high-fat ingredients, one slice of key lime pie can contain 20-30 grams of fat, including a substantial amount of artery-clogging saturated fat. For those concerned about heart health, this high level of saturated fat is one of the biggest nutritional downsides of key lime pie.


Key lime pie is also relatively high in carbohydrates, mainly from added sugars. Sources of carbs and sugar include:

  • Sweetened condensed milk – About 26 grams of carbs per 1/4 cup, the majority from added sugar.
  • Pie crust – Refined flour contributes about 15 grams of carbs per 1/8 slice.
  • Granulated white sugar – Often added to the filling, providing 4 grams of carbs per tablespoon.

One slice of key lime pie can therefore contain around 40-50 grams of carbs, comparable to other desserts like cake, ice cream, and apple pie. However, key lime pie does have a slightly lower carb count than some items like cookies, brownies, and cupcakes which can provide 50-60 carbs in a serving.

Protein and Micronutrients

Compared to calories, fat, and carbohydrates, key lime pie is not a significant source of protein, vitamins, or minerals. Protein mainly comes from the eggs, providing around 3-5 grams per slice. As for micronutrients, key lime pie provides small amounts of calcium and vitamin A, but does not offer much nutritional value relative to its calorie density.

How Does It Compare to Healthy Desserts?

Compared to more nutritious lower calorie desserts like fresh fruit, key lime pie is clearly not a great option if your main priority is health value. For example:

  • 1 cup of sliced strawberries provides 50 calories, 0 grams of fat, and 13 grams of carbs
  • 1 cup of blueberries provides 84 calories, 0 grams of fat, and 21 grams of carbs
  • 1 medium apple provides 95 calories, 0 grams of fat, and 25 grams of carbs

Versus key lime pie which provides a minimum 400 calories and 20 grams of fat per serving. The fruit options are clearly superior from a nutrition standpoint, packed with fiber, vitamins, antioxidants, and cancer-fighting compounds with a fraction of the calories, fat, and carbs.

Ways to Lighten Up Key Lime Pie

If you want to enjoy key lime pie but reduce the calorie density and fat content, there are several substitutions you can make:

  • Use reduced-fat/fat-free sweetened condensed milk
  • Substitute half the butter in the crust with heart-healthy fats like almond or avocado oil
  • Replace some egg yolks with egg whites
  • Use a whole-grain flour in the crust
  • Top with fresh fruit for added nutrition
  • Offer smaller slice sizes

With simple tweaks like these, you can shave off calories, fat, and carbs from key lime pie to make it a bit lighter.

The Bottom Line

Key lime pie can certainly be enjoyed in moderation as an occasional treat. But with its high calorie, fat, and sugar content, it is one of the more fattening dessert choices out there. Just a single slice can provide nearly a third of your daily calorie needs and over half of the recommended daily limit for saturated fat. If weight management or heart health are concerns, key lime pie should be consumed sparingly as part of an overall healthy, balanced diet focused on fruits, vegetables, lean proteins, and whole grains.


Key lime pie is an indulgent dessert that, while delicious, is quite high in calories, fat, and sugar compared to healthier options like fruit. Consuming key lime pie and other similar desserts only occasionally and in small portions is recommended as part of a balanced diet and active lifestyle.

Dessert Serving Size Calories Total Fat (g) Carbs (g)
Key lime pie 1 slice 500 25 45
Apple pie 1 slice 385 15 50
Cheesecake 1 slice 320 20 25
Chocolate cake 1 slice 390 17 49

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