Diet and Zero-Sugar Drinks: Are They Healthy? Better Alternatives That Actually Work

Many people switch from regular cola to “zero sugar” or “diet” versions and feel they have made a healthy choice. It is better than a sugary drink in terms of sugar and calories — but the evidence says it should not become your main drink.

What the evidence says about sweeteners

• WHO guideline (May 2023): non-sugar sweeteners (like aspartame, sucralose, stevia, acesulfame K) should not be used to control body weight. Reviews found no long-term benefit for body fat, and long-term use was associated with a higher risk of type 2 diabetes and heart disease in observational studies. This evidence is of low certainty — it shows association, not proof. The guideline does not apply to people who already have diabetes.
• Aspartame (July 2023): IARC classified it as “possibly carcinogenic” (group 2B) based on limited evidence, while the JECFA expert committee kept the acceptable daily intake at 40 mg/kg body weight. A 60 kg adult would need to drink many cans a day to reach that. So: no need to panic, but no reason to treat it as healthy.

Choose an alternative based on what you miss

If you miss…	Try	Keep in mind
The fizz	Plain sparkling water (only water + carbon dioxide)	May cause bloating or worsen reflux; club soda can have sodium; flavoured versions may have sweeteners or acids
Flavour	Infused water: cucumber-mint, ginger-mint, tulsi-cucumber, orange peel	It is not a “detox” or fat-burning drink. Citrus water is acidic — drink with meals, don’t sip all day
Caffeine	Unsweetened black, green or tulsi tea; black coffee or decaf	Up to about 400 mg caffeine/day is generally safe for healthy adults (FDA); avoid close to bedtime
A post-meal drink	Plain chaas: curd + 2–3 parts water + roasted jeera, mint	Little or no salt if you have high BP, kidney or heart disease
Natural sweetness	Unsweetened coconut water — occasionally	Has natural sugar; high potassium can be unsafe in kidney disease
Something filling	Plain milk	Has calories; avoid flavoured milk with added sugar

Replacing one sugary drink a day with water, unsweetened tea or coffee was linked to a lower risk of type 2 diabetes in a large European study (O’Connor et al., 2015). This is observational — it shows a link, not proof — but it fits with everything else we know about sugary drinks.

Drinks that only look healthy

Drink	Why to be careful
Fruit juice and smoothies	Juice sugars count as free sugars (WHO). No fibre, less filling — eat the whole fruit instead
Honey or jaggery lemonade	“Natural” but still free sugar and calories
Kombucha	Sugar, acidity and alcohol vary; gut-health claims are stronger than the evidence
Vitamin or flavoured water	Often has sugar, juice concentrate or sweeteners
Tonic water	Not the same as soda water — usually sweetened
Sports and electrolyte drinks	Not needed for normal daily activity; useful only in long, intense exercise or heavy sweating
ORS	A medical treatment for dehydration from diarrhoea or vomiting — not a daily wellness drink
Packaged jaljeera, sweet lassi	Can be high in sugar or salt

Simple replacement guide

1. Miss the fizz → plain sparkling water
2. Want flavour → infused water or unsweetened iced tea
3. Want caffeine → unsweetened tea, coffee or decaf
4. After meals → plain chaas
5. Want sweetness → occasional unsweetened coconut water or a whole fruit

Key takeaways

1. Diet drinks are better than sugary drinks, but not health drinks.
2. WHO advises against using sweeteners for weight control.
3. Aspartame: “possibly carcinogenic” with limited evidence — normal intake is within safe limits.
4. Water is the best everyday drink; choose alternatives by what you miss.
5. Juice, honey drinks, sports drinks and ORS are not everyday “healthy” drinks.

Sources

1. WHO. WHO advises not to use non-sugar sweeteners for weight control (guideline, May 2023) — no long-term benefit for body fat; possible links to diabetes and heart disease (low-certainty evidence)
2. WHO. Aspartame hazard and risk assessment results released — IARC & JECFA (July 2023) — “possibly carcinogenic” (2B, limited evidence); safe intake limit of 40 mg/kg/day unchanged
3. WHO. Guideline: Sugars intake for adults and children (2015) — free sugars — including juice and honey — under 10% of energy
4. O’Connor L et al. Sweet beverage intake and type 2 diabetes, and substitution with alternative beverages, Diabetologia (2015) — replacing a daily sugary drink with water, unsweetened tea or coffee was linked to lower diabetes risk (observational)
5. US FDA. Spilling the Beans: How Much Caffeine Is Too Much? — up to ~400 mg/day generally not linked to harm in healthy adults
6. ICMR-NIN. Dietary Guidelines for Indians (2024) — limit sugar and ultra-processed foods and drinks