Nutritional Information for Diet Coke
Diet Coke is a zero-sugar, near-zero-calorie soft drink sweetened with aspartame and acesulfame K. From a SpikeSaver perspective, it has zero carbohydrates and will not raise blood glucose. However, like its sibling Coke Zero, it is firmly NOVA 4 (ultra-processed) — the ingredient list includes phosphoric acid, citric acid, artificial sweeteners, caramel colour, and industrial flavourings. Diet Coke has a slightly different flavour profile to Coke Zero (it was never designed to taste like original Coke) but the nutritional and processing profile is virtually identical.
Nutrition per 100g
| Nutrient | Per 100g | Per serving |
|---|---|---|
| Energy | 0.4 kcal / 1.6 kJ | 1.3 kcal |
| Protein | 0g | 0g |
| Carbohydrates | 0g | 0g |
| of which sugars | 0g | — |
| Fat | 0g | 0g |
| of which saturated | 0g | — |
| Fibre | 0g | — |
| Salt | 0g | — |
Serving size: 1 can (330ml) · Source: Tesco product page, October 2025
Glucose impact
Very Low
Glucose risk
Diet Coke contains zero carbohydrates and zero sugar. It produces no direct blood glucose response. The artificial sweeteners aspartame and acesulfame K are non-caloric and do not raise blood sugar in the way that regular sugar does. Some emerging research suggests potential indirect effects on insulin sensitivity and gut microbiome, but the immediate glucose impact is zero.
Processing level
Diet Coke is NOVA 4 for the same reasons as Coke Zero: it contains aspartame and acesulfame K (artificial sweeteners), phosphoric acid, citric acid, caramel colour (E150d), and unspecified 'natural flavourings including caffeine'. These are industrial food additives that define ultra-processed products. There is no variant of Diet Coke that is not ultra-processed.
Diet Coke at Tesco
Source: Tesco product page, October 2025
5 UPF markers
5 UPF markers
5 UPF markers
5 UPF markers
5 UPF markers
*Prices were correct at the time of collection and may have since changed. Check Tesco.com for current pricing.
What to watch for when shopping
Diet Coke and Coke Zero are nutritionally almost identical — both are zero-calorie, zero-sugar, NOVA 4 drinks with the same core artificial sweeteners. The caffeine-free variant swaps caffeine for nothing but retains all other UPF markers. There is no 'clean' version of Diet Coke. If you want fizzy and zero-calorie without ultra-processing, sparkling water is the only genuine NOVA 1 option. Budget tip: the 15-pack of 330ml cans at £7.90 (£1.60/L) is the best value for regular drinkers, versus £3.58/L for a single 500ml bottle.
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