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Sliced chocolate diet soda cake on a plate dusted with cocoa powder
Low-Calorie Desserts · Healthy Chocolate

Diet Soda Chocolate Cake

August 17, 2026 Total time: 40 min Makes: 12 slices

This is the trick my mom's side of the family has been doing since before I was born, and it still gets me every time someone does not believe a cake with two ingredients can actually taste like a cake. The can of soda does the job of the eggs, the oil, and the water all at once.

The flavor changes more than you would expect depending on which diet soda you grab. Diet Dr Pepper reads almost like a spice cake, and a diet root beer is surprisingly good against the chocolate. Skip the frosting and a light dusting of cocoa powder is basically free, which is what keeps this one genuinely low calorie.

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Diet Soda Chocolate Cake

A two-ingredient chocolate cake made with just cake mix and a can of diet soda, no eggs, oil, or butter needed. An old family trick that actually works.

Prep 10 min
Cook 30 min
Total 40 min
Yield 12 slices

Ingredients

  • 1 box (15.25 oz / 432g) chocolate or devil's food cake mix
  • 1 can (12 oz) diet soda, such as Diet Coke, Diet Dr Pepper, or diet root beer, room temperature
  • Optional: cocoa powder or sugar-free powdered sweetener, for dusting

Instructions

  1. Preheat oven to 350F (325F if using a dark or nonstick pan). Grease a 9x13 inch baking pan.
  2. Empty the dry cake mix into a large bowl. Do not add the eggs, oil, or water called for on the box.
  3. Pour in the diet soda and whisk until no dry streaks remain and the batter is smooth and a little foamy. It will be thinner than a traditional cake batter, that is correct.
  4. Pour into the prepared pan and bake 28 to 33 minutes, until the top springs back when lightly touched and a toothpick comes out clean.
  5. Cool completely in the pan on a wire rack before cutting into 12 slices.
  6. Dust with cocoa powder or sugar-free powdered sweetener before serving if you want it to look finished.

Nutrition (approximate, per serving)

Calories150
Fat3g
Carbs32g
Fiber1g
Sugar18g
Protein2g

Estimated from the ingredients listed above; actual values will vary with brands and swaps.

Tips & swaps

  • The soda has to actually be diet, and it has to be carbonated. Flat soda will not give the cake the same lift.
  • Different diet sodas change the flavor more than you would expect. Diet Dr Pepper reads almost like a spice cake, root beer is surprisingly good with chocolate.
  • This works with any flavor of cake mix, not just chocolate. Diet lemon-lime soda with a white or yellow cake mix is a whole other recipe.
  • Skip a frosting if you want to keep this genuinely low calorie. A dusting of cocoa is basically free.

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