✦ Optimal hydration: zero calories ✦ UK tap water: highly regulated and safe ✦ Fluoride in fluoridated areas ✦ Calcium and magnesium vary by area

Still water is the optimal hydration beverage — zero calories, zero sugar, and freely available. UK tap water is one of the most regulated foods in the country, safe to drink, and contains fluoride (in fluoridated areas) and small amounts of calcium and magnesium depending on local geology. Adults need approximately 6-8 glasses (1.5-2 litres) of fluid per day, and plain water is the ideal source.

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Preparation note

Drink regularly throughout the day rather than large amounts at once; urine should be pale straw-coloured as an indicator of adequate hydration. Cold water may be better absorbed during exercise; room temperature is fine for everyday hydration.

Sources: NHS Water · CoFID 2021

Macronutrients per 100g

0.00
kcal
Energy
0.00
g
Protein
0.00
g
Carbs
0.00
g
Fibre
0.00
g
Fat

How to read GI & GL

GI (Glycemic Index) rates how fast the carbohydrates in a food raise blood glucose compared to pure glucose (= 100). Low GI ≤ 55 means a slow, steady rise. But GI says nothing about how much carbohydrate you're actually eating.

GL (Glycemic Load) fixes that. It multiplies GI by the actual grams of carbohydrate per typical serving: GL = GI × carbs per serving ÷ 100. This makes it the more useful number for real-world blood sugar management.

Why they can disagree — a food with low GI can still carry a high GL if the serving is large and carb-dense. Conversely, watermelon has a high GI (72) but a low GL (4) because a normal portion contains very few carbs. Always read both together.

Low GL ≤ 10 Modest total glucose impact per serving.
Medium GL 11–19 Moderate impact — manageable for most.
High GL ≥ 20 Significant carb load per serving. Consider a smaller portion.

Source: Atkinson et al., International Tables of GI & GL Values 2021, Am J Clin Nutr.

Glycemic Index & Load

55
GI Score
🟢 Low GI
14
GL / Serving
Medium Load

Low GI food — causes a slow, steady rise in blood sugar. Ideal for sustained energy, blood glucose control, and reducing insulin demand.

Glycemic Load (GL = GI × carbs ÷ 100) accounts for portion size. A moderate GL — portion size matters here.

Source: Atkinson et al., International Tables of GI & GL Values 2021, Am J Clin Nutr
Sources: NHS Water; CoFID 2021
Beverages Water 🇬🇧 CoFID 2021