Do artificial sweeteners such as sucralose (splenda) or aspartame (Nutrasweet) cause weight gain or hinder fat loss? Is diet coke bad for you?

Is Diet Coke Bad for You?

This is question that I used to wonder about myself before I did the research, because I have become increasingly concerned about the potential for various foods and eating patterns to affect the appetite (or fail to provide normal satiety).

This claim all over the Internet today that, “Artificial sweeteners make you fat.” The thing is, I was stunned at the crazy intensity with which these claims were made considering that I never saw any scientific evidence given to support it. I’ve only seen opinions, anecdotes and a 2005 epidemiological study about diet (artificially sweetened) coke that was actually misinterpreted.

So I ended up doing some investigating of my own, and if you trust the primary, peer reviewed, published research, then the answer is no, artificial sweeteners do not cause fat gain or hinder fat loss. If all else remains equal, you lose more weight if you substitute a calorie containing food or beverage with one that contains zero or close to zero calories.

There is currently no good evidence that diet coke is bad for you (i.e. causes weight gain or health complications). Even the topic of diet soda causing food overconsumption is mixed literature. The worst side-effect of diet coke is potentially poor dental health.

We need to think about getting lean and getting healthy. First, let’s consider body fat management separately, then we will come back to the health question.

People debate, which is worse: Sugar or high fructose corn syrup-laden coke, or artificially-sweetened diet coke? In regard to weight control, and if nothing else changed, you’d save about 150 calories with the diet stuff. Obesity researchers have stated that a consistent decrease of 100 calories a day is enough to make a statistically significant difference in body fat loss over time. But, then we have to ask the question of whether all else will actually remain equal. One of my very first worries with diet coke or artificially-sweetened drinks was if it stimulated more appetite. I found a few studies which investigated this question and found that artificial sweeteners did not stimulate appetite, subjective ratings of hunger or food intake.

Here’s an example from the journal, Nutrition Reviews (1):

Intense sweeteners and the control of appetite. Drenowski A.

“The sensation of sweet taste without calories has been said to increase appetite and promote food consumption. Regular use of intense sweeteners might therefore lead to a paradoxical weight gain. These alarmist reports have not been confirmed by recent experimental data. There is no evidence that the addition of an intense sweetener to a plain stimulus promotes appetite or results in increased food consumption during some later meal.”

Here’s the second example, this one from respected satiety expert Barbara Rolls, published in The American Journal of Clinical Nutrition (2):

Effects of intense sweeteners on hunger, food intake, and body weight: a review. Rolls B.

“The sweet taste of aspartame, saccharin, and acesulfame-K has been reported to increase ratings of hunger and, after saccharin consumption, to increase food intake. However, most investigators have found that aspartame consumption is associated with decreased or unchanged ratings of hunger. Even if aspartame consumption increases ratings of hunger in some situations, it apparently has little impact on the controls of food intake and body weight. Aspartame has not been found to increase food intake; indeed, both short-term and long-term studies have shown that consumption of aspartame-sweetened foods or drinks is associated with either no change or a reduction in food intake. Preliminary clinical trials suggest that aspartame may be a useful aid in a complete diet-and-exercise program or in weight maintenance. Intense sweeteners have never been found to cause weight gain in humans.”

I also looked at some studies on “cephalic-phase insulin release” (CPIR) which is the release of insulin just from sweet taste in the mouth.

This is a regular topic of discussion because some people are concerned about the “insulin spike” which occurs from tasting sweet food or drinks. The presence of and implications for CPIR are controversial and research is mixed. Some studies say sweet taste (such as aspartame) alone is enough to induce CPIR. Others studies say it is not.

But if an artificial sweetener or diet coke does stimulate CPIR, if it’s delivered with no calories, and while you are in a caloric deficit, it won’t actually matter. It won’t increase appetite, or food intake, and won’t be harmful to blood sugar regulation. It’s a non-issue in terms of weight management and some research confirms that a CPIR does not affect subjective hunger ratings or energy intake:

Sweet taste: effect on cephalic phase insulin release in men. Teff K. (3)

In this study, no significant increases in insulin was observed after subjects tasted the sweetened solutions.

A more recent study says that perception of sweet taste plus calories is what causes the problems with insulin spikes, blood sugar management and weight management (the latter because calorie containing sweet drinks, like high fructose corn syrup, are strongly associated with increased food intake that is not compensated for):

Functional magnetic resonance imaging of human hypothalamic responses to sweet taste and calories. Smeets, P. (4)

Their findings suggest that both sweet taste and energy content are required for a hypothalamic response. The combination of sweet taste and energy content will be required in triggering adaptive responses to sweetened beverages.

Although this looks like good news for weight loss seekers who drink diet cokes, it’s worth mentioning that some people speculate that there is another down side to frequent use of sweet foods, including artificial sweeteners: It may sharpen your sweet tooth and desire for sweets in general. I tend to believe that this assumption is correct. An increased desire for sweet taste over the long term, could conceivably cause a tendency towards increased calorie consumption.

But going as far as saying that “drinking diet coke makes you fat” is no different than saying, “eating at restaurants makes you fat.” We have studies saying that restaurant eating IS correlated with obesity, but obviously eating at restaurants doesn’t cause obesity, because you can eat at a restaurant and easily stay in a calorie deficit if you choose wisely. Most people simply overeat at restaurants, most of the time, so that explains the correlation.

What about artificial sweeteners and health? That would have to be a totally separate conversation for us for another day. I want to stick my neck out and vouch completely for the long term safety of artificial sweeteners. The vast majority of the published, peer reviewed data says that artificial sweeteners are not harmful, but no one can make a blanket safety statement, as we don’t know what the effect of various levels of intake will be over a lifetime.

We also can’t predict how various individuals will respond based on their existing genetic/medical predispositions, intolerances and current level of health. People are allergic and intolerant to all kinds of foods and food additives. Certainly artificial sweeteners are no different, so it is not surprising that there are adverse effect reports such as headaches given the extent of artificial sweetener usage today.

Nothing is safe for 100% of the people 100% of the time and anything can be toxic if delivered in high enough amounts, including water and oxygen! It’s the dose that makes the poison; that’s the basic premise of toxicology.

The artificial sweetener – health debate will rage on, no doubt, but the research is pretty clear on the artificial sweetener – weight loss issue. In a recent review paper published in the European Journal of Clinical Nutrition (6), Bellisle and Drenowski reviewed and summed up all of the research findings to date quite well. They wrote:

“Diet beverages have the advantage of reducing energy density of the product down to zero, something that is not easily achieved with solid or semi-solid foods. As a result, diet beverages might represent the optimal use of intense sweeteners in the context of a weight control strategy. Although they have been shown to be associated with some modest weight loss in Randomized controlled trials, intense sweeteners are not appetite suppressants. Their ultimate effects will depend on their integration within a reduced energy diet.”

The bottom line is calories. If nothing else changes in your diet and you replace a regular coke or caloric beverage with a diet coke or non caloric beverage, you will lose weight as a result of a lower caloric intake. If something doesn’t have calories and if it doesn’t stimulate appetite and concurrent or subsequent food intake, it can’t make you gain weight.

However, just because you switch to diet coke or a calorie-free artificially-sweetened beverage is no guarantee that you’ll lose weight if you overcompensate by eating more elsewhere. Want to learn more about nutrition and how to get a free calorie calculation? Click here.

 

References

1. Intense sweeteners and the control of appetite. Drewnowski A. Nutr Rev. 1995 53(1):1-7. School of Public Health, University of Michigan.

2. Effects of intense sweeteners on hunger, food intake, and body weight: a review. Rolls B. Am J Clin Nutr. 1991 53(4):872-8. Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD

3. Sweet taste: effect on cephalic phase insulin release in men. Teff KL, Devine J, Engelman K. Physiol Behav. 1995. 57(6):1089-95. Monell Chemical Senses Center, Philadelphia.

4. Functional magnetic resonance imaging of human hypothalamic responses to sweet taste and calories. Smeets, P. American Journal of Clinical Nutrition, Vol. 82, No. 5, 1011-1016, November 2005

5. San Antonio Heart Study. Sharon Fowler Presenting her findings at the annual Diabetes conference. 2005.

6. Intense sweeteners, energy intake and the control of body weight. Bellisle F, Drenowski, A. European Journal of Clinical Nutrition. June 2007. vol 61. pp 691-700

GeorgeHealth.com – Is Diet Coke Bad for You?