We've released Evidence-based Keto: Your no-hype guide to the ketogenic diet, and it's on sale until Friday night . Click here to learn more

Does diet soda inhibit fat loss?

It does not inhibit fat loss at all, and may actually suppress appetite that could help fat loss (although it does not induce fat loss per se either). Diet soda, in regards to body fat, is a carbonated inert beverage

Written by
Last Updated:

Diet Soda and Fat loss

Biochemically speaking

First, let's define 'diet soda' as any drink that is sweetened with low to no calorie sweeteners (like sucralose, aspartame, acesulfame-potassium, etc.) in order to taste like regular (sugared) soda.

In short, there are no direct causative studies that show the use of artificial sweeteners slows your metabolism or promotes fat storage.[1]

Intervention studies

The CHOICE randomized study, lasting 6 months and observing how different diet changes affect weight loss adherence, found that diet soda is an effective substitution for regular soda and had no significant differences in health or weight loss relative to water.[2] 

Data from the NHANES (03-04) study suggest that increased servings of non-caloric beverages are not related to an increase in total calories.[3] Additionally, the PREMIER trial found that a reduction in intake of non-caloric beverage is not associated with weight loss.[4]

What is the source of confusion?

The real problem is that people tend to under-estimate caloric intake. By thinking about the zero calories in the soda, they end up eating an excess of calories, thus increasing fat storage[5]. This makes the well known correlation_ (relationship) between diet soda and obesity; one does not cause the other, but they tend to co-exist. Drinking diet soda does not make one fat, but people with obesity tend to drink diet soda.

In regards to insulin, diet soda can potentially increase insulin secretion by both an anticipatory response and the artificial sweetener aspartame can (through the amino acid, phenylalanine). However, both of these insulin spikes are too small to matter practically, and the latter mechanism doesn't seem to occur at all with many commonly ingested dosages.

Devil's advocate: Diet soda for weight loss?

As mentioned on our Aspartame and Appetite page, aspartame (via phenylalanine) might also suppress appetite.

Introducing Evidence-based Keto: Your no-hype guide to the ketogenic diet

We've spent the past year analyzing the research on the keto diet, and have just released Evidence-based Keto.

Clocking in at over 200 pages with 500+ references, it's the unbiased guide you need to the ketogenic diet.

ON SALE THIS WEEK: Evidence-based Keto

Unbiased truth on keto and long-term effects on health, safety, pre-existing conditions, losing weight, and more.

Everything you need to know about the keto diet

When we asked our users what they wanted us to cover, many of them mentioned the keto diet.

So we listened. We spent the year looking up the research on the ketogenic diet to help guide you in your journey.

With Evidence-based Keto, Examine.com gives you all the scientific research, but in understandable language with tons of informative infographics. No opinion, no bias, no conflict of interest.

If you’re interested in keto, this is a must-have unbiased source.