Calories, calories calories – we are a nation becoming increasingly consumed with counting them. It’s no wonder that phrases such as, “Coke Zero weight loss”, “zero calorie caffeine drinks” and even, “zero calorie alcoholic drinks” are becoming increasingly popular in Google searches. In this article, we discuss what are the effects of diets drinks: weight gain or loss? Have a guess before you read any further!

Weight loss communities are adopting a propensity towards consuming diet drinks for weight loss; large soft drink manufacturers are very much aware of this trend and they are responding with the launch of zero calorie drinks and even a progression towards low or no sugar soft drinks.

Coke, sugar, fizzy drinks

What are in diet drinks?

Diet drinks and some of the best low sugar drinks can achieve much lower sugar and calories by replacing various ingredients with artificial sweeteners. These are man-made sugar substitutes which mimic the flavour of sugar but without the calories. Common examples include saccharin, sucralose acesulfame, aspartame, and neotame, all of which have been granted FDA approval. There is also one natural sweetener which the FDA have approved and is becoming increasingly popular – stevia.

The nutritional value of regular soda versus diet soda depicts quite a difference in terms of sugar and calories. Take, for example some beverages on the sugar free drinks list, Coke Zero or Diet Coke and compare it with the original Coca Cola drink:

Coca cola, diet coke, coke zero nutritional value, sugar

It’s evident that there is a significantly higher quantity of sugar in regular coke compared to the sugar-free alternatives. Based on the Coca Cola website, Coke Zero and Diet coke substitute sugar for a blend of acesulfame-K and aspartame, which facilitate the ability to omit sugar and thus the associated calories.

Are you interested in learning about artificial sweeteners? Comment below if you want me to write an article on this!

Do diet drinks cause weight loss?

A six-month study was conducted by dietitians on 40 participants with a body mass index of >30 to assess the impact of changes in diet soda consumption on weight loss. The group were initially discouraged from consuming diet soda drinks and encouraged to opt for water for hydration; towards the latter end of the study, they were broken into 3 groups:

  1. diet soda/no soda reduction
  2. diet soda/with soda reduction
  3. never drank diet soda

Overall observations deducted that no significant difference in weight loss was observed between the three groups, and that further research would be required to ascertain the reason for waist circumference reductions in each group.

A separate long-term study on a cohort of 749 volunteers aged 65+ assessed the relationship between consumption of diet soda and waist circumference. The study observed a dose-reponse relationship between increasing diet soda consumption and escalating abdominal circumference.

Interestingly, a survey into the grocery purchasing patterns of diet soda drinkers versus regular soda drinks identified that the diet drink consumers made more nutritionally desirable purchases in comparison to the regular soda drink consumers. This suggests that these consumers did not compensate their calories saved by purchasing additional high-energy foods.

There have been a number of studies which propose that consumption of beverages containing artificial sweeteners may suppress hunger or calorie intake, which could be considered a useful indirect effect of diet soda drinks for people looking for rapid weight loss tips and tricks. Additionally, randomised controlled studies suggest that artificial sweeteners may contribute to a reduction in waist circumference, weight and body mass.

In summary, there is limited evidence that diet drinks directly cause weight loss. So while many people will still drink Coke Zero and other sugar free drink alternatives for weight loss, it may stop hunger when dieting, but it won’t directly lead to reduced weight, only calorie deficits can accomplish this.

I personally try to lean towards water flavour enhancers such as Twinings Cold In’Fuse which comes in a range of flavours, or Robinsons SQUASH’D which has no sugar and no calories (I love the summer fruits flavour). These are excellent low sugar drinks for kids and adults alike.

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Coke, beverages, zero sugar, low calorie drink

Do diet drinks cause weight gain?

Diet drinks typically don’t have enough calories to induce much of a weight gain. Now we do know that certain low calorie drinks may contain anywhere between 2-30 calories per 100ml, if a person was to consume large quantities of such a drink, it could be possible that overtime, this habit could lead to weight gain.

What about indirectly?

When reviewing research-based studies on diet drinks and weight gain, there is no direct correlation between weight gain (or weight loss for that matter) and diet drinks/artificial sweetener consumption. Just because someone consumes zero calorie drinks/sugar free drink, it doesn’t equate to weight gain; eating in a calorie surplus, on the other hand, will ultimately induce weight gain.

Many of the studies conducted observed that diet drink consumers tend to feel entitled to eat more sugar. Such people psychologically feel that since they are not consuming sugar in their fizzy drinks now that they’ve moved to the low sugar version, they can compensate by eating the sugar in other foods. Consequently, many people offset their potential weight loss which could have been achieved from ditching the sugar-laden fizzy drinks.

By now, most of us are familiar with the concept that calories in should equal calories out in order to maintain weight. If people are not in a calorie deficit (e.g. if they don’t reduce their overall daily sugar intake), then they shouldn’t expect to observe a weight loss reduction. However, someone who swaps a nutritive drink (containing calories) for a non-nutritive drink and makes no other change to their diet, could see a reduction in weight.

So, do diet drinks make you gain weight? The short answer is no, not directly on their own.

Sparkling water, low sugar drink, low calorie drink


  • Diet drinks alone won’t solely contribute to weight loss, only a calorie-deficit will achieve this
  • Replacing sugary drinks with artificially sweetened alternatives may contribute to weight loss
  • Limited scientific evidence exists to convict diet drinks of causing weight gain
  • Flavoured water may be a healthier alternative to fizzy drinks

What’s your opinion on diet drinks? Do you opt for the regular or the low calorie version? I’d love to hear your thoughts.


Binkley, J. and Golub, A. (2007). Comparison of grocery purchase patterns of diet soda buyers to those of regular soda buyers. Appetite, 49(3), pp.561-571.

Boyles, S. (2010). Does Diet Soda Really Cause Weight Gain? What Experts Say. [online] WebMD. Available at: [Accessed 25 Feb. 2020].

Coca Cola (2020). Coca-Cola original taste Nutritional Info & Ingredients | Coca-Cola IE. [online] Available at: [Accessed 28 Feb. 2020].

Fowler, S., Williams, K. and Hazuda, H. (2015). Diet Soda Intake Is Associated with Long-Term Increases in Waist Circumference in a Biethnic Cohort of Older Adults: The San Antonio Longitudinal Study of Aging. Journal of the American Geriatrics Society, 63(4), pp.708-715.

Lindorf, K., Pobocik, R., Nielson, K., Adams, T. and Williford, J. (2011). Changes in Diet Soda Consumption Do Not Affect Weight Loss or Waist Circumference. Journal of the American Dietetic Association, 111(9), p.A40.

Matthews, M. (2020). What 7 Studies Say About Artificial Sweeteners and Weight Loss – Legion Athletics. [online] Legion Athletics. Available at: [Accessed 25 Feb. 2020]

Strawbridge, H. (2020). Artificial sweeteners: sugar-free, but at what cost? – Harvard Health Blog. [online] Harvard Health Blog. Available at: [Accessed 28 Feb. 2020].

Categories: Blogs


Bob · 28/02/2020 at 1:35 PM

I’m a diabetic and I’ve taken my blood sugar after drinking a coke zero. It exploded my blood sugar reading and came right back to where it was within 30 minutes of taking it. I don’t know what artificial sugars do. I would like to see an article on artificial sugars. It would be very illuminating. Thanks, Bob

    Sharon · 28/02/2020 at 1:53 PM

    Hi Bob,

    That’s fascinating, it seems to be a contradiction to what you would expect to occur considering these are formulated with the intention of having little to no sugar. I’ll add artificial sweeteners to my to-do list!

    Thanks for the feedback,

Jeff · 29/02/2020 at 12:55 PM

I found your article very interesting with good facts and statistics to help us understand the pros and cons of diet drinks, I have eliminated soft drinks from my diet completely which has got my weight back to where it should be and easier for me to manage. I feel that if you are living on even diet drinks you could be sabotaging your weight management plan, and you can do like I do and prepare your own enhanced water drinks at home costing you very little if you are on a budget.

What is your input on these artificial sweeteners and ingredients in diet drinks as a possible contributor to chronic disease?

Just curious what you think about this,


    Sharon · 29/02/2020 at 5:41 PM

    Hi Jeff,

    I’m delighted to hear you enjoyed it! That’s a great idea and certainly something I’m moving towards as it’s very easy to become accustomed/addicted to fizzy drinks! I know there have been a range of studies linking artificial sweeteners to chronic diseases. Of the studies I’ve reviewed, none of them have conclusively correlated artificial sweetener consumption with chronic disease. That’s not to say the relationship exits, we just merely need more well-controlled studies to determine if such an association exits.

    Hope that answers your query.


marketa · 29/02/2020 at 1:08 PM

Hi Sharon,
I don’t like bubbly drinks at all so have never had a problem with having to cut them out for weight maintenance or loss. My children, however love coke and fanta and other sugary drinks and I worry quite a bit. However, I don’t like the idea of them consuming artificial sweetners. It’s really difficult because of course, sugar isn’t good but is it better than further artificial products?

    Sharon · 29/02/2020 at 5:44 PM


    It’s a great advantage that you don’t enjoy such drinks. Pity it hasn’t transitioned down to your kids! There are many people of that opinion, but without clear substantial evidence definitively stipulating the adverse effects of artificial products, it’s difficult to say. Hopefully research will step up and offer us an answer sooner than later.


David · 01/03/2020 at 2:05 PM

Hi Sharon

Good piece again, well done. Diet drinks is a complicated issue as have been proven to be anything but.


    Sharon · 02/03/2020 at 9:17 PM

    Hi Dave,

    Thanks so much, I agree – people can be on the fence when it comes to diet v regular drinks.


Gaurav · 01/03/2020 at 3:44 PM

Excellent article Sharon. Very well researched and insightful. I completely went off sugar and hit a 500 – 1k calorie deficit to lose weight some time ago and when I hit my goal I’ve tried to maintain calories.
Sharing your site with my friends who’re looking to lose weight but don’t know where to start.

    Sharon · 02/03/2020 at 9:16 PM

    Hi Joshi,

    Wow, that’s really admirable, it can be very difficult to achieve such a calorie deficit, not least maintain it!

    Thanks for sharing it with your friends, I really appreciate it!

Rick · 02/03/2020 at 1:16 AM

I have always wondered about which is more of the evil, sugar drinks vs artificial sweeteners. On top of that I have a hard time believing in what is written on the container. These companies have lied to us many times before so why should we believe them today.

For myself I never grew up drinking sugar drinks but I do enjoy a nice can of Pepsi with pizza or fish n chips. That would be the extent of it because my body seems to say “I have enough”. Perhaps it’s my mind being so conscious of it – I don’t know.

As for the man made sugar – forget it. If it’s not natural I stay way from it.
Great article thanks for sharing and yes I would love to read about the artificial sweeteners.


    Sharon · 02/03/2020 at 9:15 PM

    Hi Rick,

    It’s great you/your body is in such a frame of mind, many people develop unhealthy addictions to fizzy drinks and have so much difficulty weaning themselves off it.

    Thanks for the feedback, stay tuned for the article, I’ll hopefully be writing it soon.

Stacy · 02/03/2020 at 1:28 PM

As a personal trainer who works with an older demographic I try to help clients kick out all sugar including artificial sweeteners. I understand the need for some satiation during weight loss and really appreciated your strategy of water flavour enhancers such as Twinings Cold In’Fuse or Robinsons SQUASH’D. I plan to research these alternatives as a better substitute to both diet soda and regular soda. The sooner I can help clients break the sugar addiction the sooner I can get them results.

    Sharon · 02/03/2020 at 9:14 PM

    Absolutely, I personally feel that in spite of research not yet conclusively reprimanding artificial sweeteners, it’s best to stick to as much natural food as possible.

    I hope my article can be of benefit to you and your clients!


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