Aspartame, blood sugar and weight in people with type 2 diabetes
What it found
Aspartame may raise stress hormones, change gut bacteria and increase weight gain instead of helping control blood sugar.
These findings come from studies in animals and a small number of people.
What they found
Animal and lab studies
Stress hormone cortisol
In rats, taking aspartame for 90 days raised levels of the stress hormone corticosterone. The author suggests this extra cortisol could block insulin from working properly and lead to insulin resistance.
Gut bacteria changes
Rats that drank water with low doses of aspartame for eight weeks had higher fasting blood sugar and more of a gut bacteria group called Enterobacteriaceae. Mice on a high fat diet with aspartame for eleven weeks also showed gut bacteria changes and worse blood sugar control.
Studies in people and animals
Blood sugar levels
In one trial of 64 fasting people, an aspartame drink made no difference to blood sugar after 5, 10 or 15 minutes. But in another study of 10 people, blood sugar fell in 40% of subjects and rose in 20%. In mice and zebra fish, aspartame raised fasting blood sugar.
Weight and appetite
Rats given aspartame gained more weight than rats given sugar, even when total calories were the same. In people, drinking diet sodas with aspartame was linked to a higher body mass index in both adults and school children.
Other findings
Amounts found in drinks
Diet fizzy drinks contain 150 to 200 mg of aspartame per 360 ml serving. Non fizzy drinks usually have 140 mg per 240 ml serving. European authorities set a daily limit of 40 mg per kg of body weight, while US authorities set it at 50 mg per kg.
What the authors conclude
- They conclude that aspartame use in people with type 2 diabetes may cause weight gain rather than weight loss.
- They suggest aspartame may act as a chemical stressor that raises cortisol and blocks insulin pathways, and may cause oxidative stress that worsens diabetes complications.
- They advise that international guidelines on aspartame should be reviewed because of these concerns.
How it was done
People with type 2 diabetes are often told to use aspartame instead of sugar to help manage their blood sugar. The author wanted to gather evidence on whether aspartame might actually make diabetes worse.
The author gathered and examined published studies on aspartame and type 2 diabetes. The work looked at research in mice, rats, zebra fish and people, including trials giving aspartame for up to 90 days or 11 weeks.
What it can’t tell you
- Most of the detailed findings on how aspartame affects cells, organs and hormones come from animal studies. Results from animals cannot directly show what happens in people.
- The human studies mentioned had small numbers of participants and relied on people reporting their own intake, which may not be accurate.
- Because this is a review of many different studies, it can point out links but cannot prove that aspartame causes these effects in people.
Who paid
- Authors work at
- University of Pretoria, South Africa
The paper
- Title
- Aspartame: Should Individuals with Type II Diabetes be Taking it?
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Choudhary AK (2018). Aspartame: Should Individuals with Type II Diabetes be Taking it?. Current diabetes reviews. doi:10.2174/1573399813666170601093336Free full textPubMed 28571543DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error