The Best & Worst Keto Tonic Waters

‘Tis the season to be drinking (if you’re that way inclined) and Gin & Tonic is one of Britain’s favourite tipples. Gin is fine from a keto point of view (as long as you don’t go for one with lots of added sugar), but finding the right low-carb tonic water can be a minefield! Especially as not all light or diet tonics are actually carb-free! So, here’s my rundown of the best and worst tonic waters for keto dieters!

The Best Zero Carb Tonic Waters

Essential Waitrose Sugar Free Indian Tonic Water
Carbs per 100ml 0g
Of which sugars 0g
Sweetened with sucralose

Morrisons Diet Indian Tonic Water
Carbs per 100ml 0g
Of which sugars 0g
Sweetened with Sweeteners (Acesulfame K, Sucralose)

Morrisons Diet Tonic Water with a Hint of Lime
Carbs per 100ml 0g
Of which sugars 0g
Sweetened with Sweeteners (Acesulfame K, Sucralose)

Sainsbury’s Diet Indian Tonic Water with Lime
Carbs per 100ml <0.5g
Of which sugars <0.5g
Sweeteners:Acesulfame K, Sucralose.

Sainsbury’s Diet Indian Tonic Water
Carbs per 100ml 0g
Of which sugars 0g
Sweeteners: Acesulfame K, Sucralose;

Schweppes Slimline Tonic Water
Carbs per 100ml 0g
Of which sugars 0g
Sweetener (Aspartame)

Schweppes Low Calorie Elderflower Tonic Water
Carbs per 100ml 0g
Of which sugars 0g
Sweetened with Sweeteners (Aspartame, Acesulfame K)

Schweppes Slimline Tonic Water with Lemon Zest
Carbs per 100ml 0g
Of which sugars 0g
Sweetened with Sweetener (Aspartame)

Skinny Tonic Indian Tonic
Carbs per 100ml 0g
Of which sugars 0g
Sweetened with stevia

Tesco Low Calorie Indian Tonic Water
Carbs per 100ml 0g
Of which sugars 0g
Sweetened with Sweeteners (Acesulfame K, Sucralose).

Tesco Low Calorie Indian Tonic Water with Elderflower
Carbs per 100ml 0g
Of which sugars 0g
Sweetened with Sweetener (Acesulfame K)

Tesco Low Calorie Indian Tonic Water with Lime
Carbs per 100ml 0g
Of which sugars 0g
Sweetened with Sweeteners (Acesulfame K, Sucralose).

Essential Waitrose Sugar Free Tonic water with Lemon
Carbs per 100ml >0.5g
Of which sugars >0.5g
Sweetened with sweetener sucralose

Essential Waitrose Sugar Free Indian Tonic Water & Lime
Carbs per 100ml >0.5g
Of which sugars >0.5g
Sweetened with sweetener sucralose

Tonics to Avoid (Ordered from Best to Worst for Carb Content)

Sainsbury’s Light Indian Tonic Water, Taste the Difference
Carbs per 100ml 2.9g
Of which sugars 2.9g
Sweetened with fructose (fruit sugar)

Morrisons Indian Tonic Water
Carbs per 100ml 3.4g
Of which sugars 3.4g
Sweetened with sugar, Sweetener (Acesulfame K)

Asda Extra Special Light Tonic Water
Carbs per 100ml 3.5g
Of which sugars 3.5g
Sweetened with fructose syrup

Tesco Indian Tonic Water
Carbs per 100ml 3.6g
Of which sugars 3.6g
Sweetened with sugar, sweeteners (Sucralose, Sodium Saccharin)

Fever Tree Refreshingly Light Indian Tonic Water
Carbs per 100ml 3.8g
Of which sugars 2.9g
Fructose (Fruit Sugar)

Fever Tree Refreshingly Light Lemon Tonic Water
Carbs per 100ml 4.2g
Of which sugars 4.2g
Sweetened with fructose (fruit sugar)

London Essence Co Grapefruit & Rosemary Tonic Water
Carbs per 100ml 4.2g
Of which sugars 4.2g
Sweetened with fructose (fruit sugar)

London Essence Co. Original Indian Tonic Water
Carbs per 100ml 4.3g
Of which sugars 4.3g
Sweetened with fructose (fruit sugar)

London Essence Co. Orange & Elderflower Tonic Water
Carbs per 100ml 4.3g
Of which sugars 4.3g
Sweetened with fructose (fruit sugar)

Fever Tree Refreshingly Light Aromatic Tonic Water
Carbs per 100ml 4.3g
Of which sugars 4.3g
Sweetened with fructose (fruit sugar)

Asda Extra Special British Elderflower Tonic Water
Carbs per 100ml 4.5g
Of which sugars 4.5g
Sweetened with sugar

Asda Extra Special Clementine and Cinnamon Tonic
Carbs per 100ml 4.5g
Of which sugars 4.5g
Sweetened with sugar

Asda Extra Special Pink Grapefruit and Peach Tonic
Carbs per 100ml 4.7g
Of which sugars 4.7g
Sweetened with sugar

Fever Tree Refreshingly Light Elderflower Tonic Water
Carbs per 100ml 4.7g
Of which sugars 4.7g
Sweetened with fructose (fruit sugar)

Fever Tree Refreshingly Light Clementine Tonic Water with Cinnamon
Carbs per 100ml 4.7g
Of which sugars 4.7g
Sweetened with fructose (fruit sugar)

Sainsuburys Indian Tonic Water
Carbs per 100ml 4.8g
Of which sugars 4.8g
Sugar and Sweeteners:Acesulfame K, Sucralose.

Fever Tree Refreshingly Light Mediterranean Tonic Water
Carbs per 100ml 4.8g
Of which sugars 4.8g
Sweetened with fructose (fruit sugar)

Merchant’s Heart Light Tonic Water
Carbs per 100ml 4.8g
Of which sugars 4.8g
Sweetened with sugar, Sweeteners (Acesulfame-K, Sucralose)

Fever Tree Light Cucumber Tonic Water
Carbs per 100ml 4.8g
Of which sugars 4.8g
Sweetened with fructose (fruit sugar)

Essential Waitrose Indian Tonic Water
Carbs per 100ml 4.9g
Of which sugars 4.9g
Sweetened with sugar

Asda Extra Special British Cucumber & Mint Tonic Water
Carbs per 100ml 4.9g
Of which sugars 4.9g
Sweetened with sugar

Schweppes Tonic Water
Carbs per 100ml 4.9g
Of which sugars 4.9g
Contains sugar and sweetener: sodium saccharin

Fever Tree Indian Tonic Water
Carbs per 100ml 7.1g
Of which sugars 7.1g
Cane Sugar

Fever Tree Premium Indian Tonic Water
Carbs per 100ml 7.1g
Of which sugars 7.1g
Sweetened with cane sugar

Merchant’s Heart Hibiscus Tonic Water
Carbs per 100ml 7.4g
Of which sugars 7.4g
Sweetened with sugar

Double Dutch Indian Tonic Water
Carbs per 100ml 7.5g
Of which sugars 7.5g
Sweetened with sugar

Fentimans Natural Pink Grapefruit Tonic Water
Carbs per 100ml 7.7g
Of which sugars 7.7g
Sweetened with sugar

Fentimans Valencian Orange Tonic Water
Carbs per 100ml 7.7g
Of which sugars 7.7g
Sweetened with sugar

Sainsbury’s Indian Tonic Water, Taste the Difference
Carbs per 100ml 8.0g
Of which sugars 7.7g
Sweetened with sugar

Fever Tree Aromatic Tonic Water
Carbs per 100ml 8.2g
Of which sugars 7.8g
Sweetened with sugar

Fever Tree Elderflower Tonic Water
Carbs per 100ml 8.5g
Of which sugars 7.8g
Sweetened with Cane sugar

Merchant’s Heart Pink Peppercorn Tonic Water
Carbs per 100ml 8.8g
Of which sugars 8.8g
Sweetened with sugar

Merchant’s Heart Tonic Water
Carbs per 100ml 8.8g
Of which sugars 8.8g
Sweetened with sugar

Merchant’s Heart Floral Aromatics Tonic Water
Carbs per 100ml 8.9g
Of which sugars 8.9g
Sweetened with sugar

Fever Tree Mediterranean Tonic
Carbs per 100ml 9.0g
Of which sugars 7.4g
Sweetened with cane sugar

As you can see tonics vary wildly in their carb content, even those that are marketed as ‘light’ or ‘diet’. If I’ve missed any off the list that you think are good (or terrible) please let me know in the comments below!

While I’ve tried hard to get an accurate list errors are possible so its worth double-checking the information for yourself. Sources are the UK online grocery stores for Sainsburys Asda, Tesco, Waitrose and Morrisons.