Losing weight can be tough because you need to reduce your calories to do this. This can be a problem for some people who love their sweet drinks, so they go to drinking artificially sweetened sodas. Unfortunately, these may not really benefit many people who are losing weight and may even worsen their efforts.

In a recent study published in PLoS One, researcher followed 9,722 adults (1,454 men and 8,268 women) for an average of 10 years to see if using low-calorie sweeteners were beneficial for losing weight. The results were a bit surprising, for those who used low-calorie sweeteners in their foods had a 53% higher incidence of abdominal obesity and a fairly dramatic increase in body mass index compared to those who didn’t drink these sodas, cumulative over the 10 year period.

Even participants who had a normal body weight with no obesity at the beginning of the study had a significantly greater risk of becoming overweight and/ or obese, and had higher abdominal obesity than those who didn’t use low-calorie sweeteners. This included sodas and all other food products that needed sweetening.

A large study performed in San Antonio, TX showed similar results, but they evaluated low-calorie sodas only and found an increase in body weight and abdominal obesity when these types of sodas were used.[1], [2] Substituting low-calorie sweetened foods, including beverages, for sugar-sweetened beverages can certainly decrease your total calories ingested in a day. However, they do not appear to help in weight-loss and even appear to induce worsening obesity, especially in the abdomen.

There are many hypotheses that could explain why low-calorie sweetened foods have these effects. One is that low-calorie sweeteners do not have an affect on the brain satiety centers, resulting in you staying hungrier and eating more. This could be because the reward center in your brain likes “sweetness” and it’s not being satisfied.

Perhaps people may be just fooling themselves that they are reducing their calories by drinking diet drinks. They lay in a false sense of security when they think that just drinking diet sodas will help them lose weight. Doing so may give them a false sense of doing the right thing, but the results, at least as suggested in this study, prove otherwise.

Another possible mechanism is that a diet with low-calorie sweeteners may change the gut flora (microbiome), resulting in abnormal energy metabolism of the gut flora. This dysbiosis may result in weight gain, as demonstrated in rat models.[3] Certainly having the correct microbiome for losing weight is an important factor in losing weight.

Perhaps one other possible explanation is that those consuming low-calorie sweeteners have not been able to change their metabolism to fat-burning instead of carb burning mode. Doing a ketogenic diet does this by decreasing all types of carbs, not just those from sugar. There’s no doubt that sugar is not good for you, but just eliminated sugar and drinking low-cal sodas and foods is obviously just not enough.

If you have a problem with being overweight or obese and want to lose weight, consider a pathway that works, such as our diet program, The True Diet. We can help put you into that fat-burning mode instead of burning carbs. Not only can you lose weight, but you can also keep the excess weight off when you do the program and then do our maintenance program.

In conclusion, low-calorie sweetener use may not help you lose weight. In fact, it may actually increase your weight, and particularly weight inside your abdomen (abdominal obesity). There are many theories for why this happens. The True Diet program may be a viable alternative for you to lose weight than relying on just cutting back sugar calories, especially by using low-calorie sweeteners.

[1] Fowler SP, Williams K, Resendez RG, Hunt KJ, Hazuda HP, Stern MP. Fueling the obesity epidemic? Artificially sweetened beverage use and long-term weight gain. Obesity. 2008;16(8):1894–900. pmid:18535548. https://doi.org/10.1038/oby.2008.284

[2] Google Scholar

  1. Fowler SPG, Williams K, Hazuda HP. 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. 2015;63(4):708–15. pmid:25780952. https://doi.org/10.1111/jgs.13376

[3] Google Scholar

  1. Abou-Donia MB, El-Masry EM, Abdel-Rahman AA, McLendon RE, Schiffman SS. Splenda Alters Gut Microflora and Increases Intestinal P-Glycoprotein and Cytochrome P-450 in Male Rats. Journal of Toxicology and Environmental Health, Part A. 2008;71(21):1415–29. pmid:18800291. https://doi.org/10.1080/15287390802328630