Does diet soda really cause weight gain?

By: Feb 27, 2012
Diet soda and weight gain

Learn the truth about diet soda and it's effects on weight loss & weight gain.

Have you ever watched the thin person next to you guzzle one sugar-sweet soda after another while you sipped your diet soda and wondered why you can’t lose weight? You aren’t alone, and there may be an explanation on the horizon.  Artificial sweeteners have garnered lots of global press for the past quarter of a century. Included in that press is the debate of diet versus sugared soda and their effects on weight loss and weight gain.

Reports on research studies from impressive groups like the American Diabetes Association (ADA), Purdue University, and Boston University have brought to our attention some of the effects of diet sodas on our overall health. These researchers set out to study the effects of diet sodas on metabolism. Collecting data from approximately 15,000 people over a ten-year period, researchers got lots of interesting data and that one consistent theme was that diet soda is not the panacea for maintaining healthy weight that we all thought it was.


Girth:  Most people know that a heavier middle is a precursor for heart disease, especially as we age. The ADA’s first diet soda study of two focused on the elderly and found a shocking 500% increase in waist circumference for those who drank at least two diet sodas daily as compared to those who drank none. Is this because the elderly persons in the study were less mobile, didn’t exercise, or ate diets generally unhealthy?

Blood Glucose:  ADA also looked at the effects of diet sodas on blood glucose, studying people prone to developing diabetes. The people with diets that included aspartame had increased blood glucose over those without the sugar substitute. This tells us diet sodas have an adverse effect on people with a predisposition to diabetes. What about the rest of us?

Heart Attack and Stroke:  For almost ten years, the Northern Manhattan project studied 2,500 people. The results weren’t encouraging; people who drank diet sodas daily had a higher chance for stroke and heart attacks. The number of fatal cardiovascular events was surprising. Of the 2,500 participants, 559 (22%) had a heart attack or stroke and 338 (60%) of those were fatal. This study was somewhat more scientifically sound since it stratified participants by smokers, diabetics, waistline measurements, alcohol consumption, ethnicity, and other screening factors.  Unfortunately, no definitive cause was found for any of the results. Are we destined for a heart attack or stroke if we drink diet sodas?

Sweet Tooth:  Some theories drawn from the studies above as well as others suggest that artificial sweeteners are addictive and increase the craving for sweets – sweets that are frequently hidden in carbohydrate-laden breads, crackers, and canned foods. The problem in evaluating diet sodas and their relationship to weight gain or loss is that artificial sweeteners and sugars and their wide variety of sources are not all regulated. Between high-fructose corn syrup, sugar alcohols, novel sweeteners, natural sweeteners, etc. it’s almost impossible to figure out who studied exactly what. One fact is clear, if you have a sweet tooth – craving for calorie-laden carbohydrates or sugar in any form (artificial or otherwise) weight control is not easy. What do we do?

Most of the studies to evaluate the relationship (if any) between weight gain and diet sodas have been observational studies. In other words, reliable quality control parameters weren’t in place to scientifically record and substantiate the findings. Preliminary data appears to show a link between elevated blood glucose, weight gain, and cardiovascular events in people who drink over two diet sodas a day, but credible studies with controls in place need to be done before declaring diet sodas harmful.

In the meantime, I'll be sticking to water!