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Do Artificial Sweeteners Promote Weight Gain?

The use of artificial sweeteners, particularly in beverages, is widespread and has been extensively promoted by the food and beverage industry in “diet products”. Paradoxically, however, several large recent studies have consistently shown that increased use of such “diet products” is associated with weight gain.

The same is true in a new study by Sharon Fowler and colleagues from The University of Texas, San Antonio, TX, just out in OBESITY. In this study, Fowler and colleagues examined the relationship between artificially sweetened beverage (ASB) consumption and long-term weight gain in the San Antonio Heart Study. From 1979 to 1988, height, weight, and ASB consumption were measured among 5,158 adult residents of San Antonio, Texas. Seven to eight years later, 3,682 participants (74% of survivors) were re-examined.

Consuming >21 ASBs/week (vs. none) was associated with almost-doubled risk of becoming overweight or obesity in participants with a BMI <30 at baseline. These findings raise the question whether AS use might be fueling–rather than fighting–our escalating obesity epidemic.

If ASBs have no calories, how can this be?

The authors provide several suggestions for this relationship in their paper:

1. Use of artificial sweeteners may just be a “marker” of people who tend to have a weight problem: This sounds quite logical – of course, someone who is experiencing weight gain for whatever reason may be more likely to switch to artificial sweeteners. In the end they still gain weight, but now it looks like using these products is the problem, when it’s not – in fact without these products the individuals may have ended up gaining even more weight.

2. Use of artificial sweeteners may indirectly cause weight gain: There could be several reasons for this including the fact that people make up the lost calories from sugar by increasing their intake of fat (in the end the body always gets the calories it needs). Users of “diet” products may also overcompensate with other foods (because I am having a diet pop (saving = 180 KCal), I can afford to have another burger (overcompensation = 400 KCal) resulting in a net gain of 220 KCal). Thirdly, because artificial sweeteners are so sweet, they may in the long-term desensitize your sweet sensation so that when you do use actual sugar, you tend to need more sugar (= more calories) to experience the same “sweetness”.

3. Use of artificial sweeteners may directly cause weight gain: There is evidence that at least in some people artificial sweeteners or sweet taste itself may increase hunger, cravings or food intake. A few studies have suggested that artificial sweeteners can increase insulin levels and as a result promote hypoglycemia, resulting in hunger. Lastly, at least in animal studies, high levels of aspartame are toxic to neurons in the arcuate nucleus of the hypothalamus, a key area for the regulation of hunger and appetite.

Whatever the reason, my advise to my patients is to lay off the artificial sweeteners. Rather, if it must be, a touch of real sugar lightly sprinkled on the food or even half your usual amount in beverages may be a better way to go. I, several years ago, went from two teaspoons of sugar in my coffee to no sugar at all – it took me a while to adjust, but today I no longer like sweetend coffee (I do still have a touch of sugar in my tea).

Edmonton, Alberta


  1. It’s true- The tastebuds are truly remarkable at adjusting to less or more of a basic taste. Exactly the same suggestion can be made of salt.
    In addition to the health savings, cutting down on the additives can allow us to taste the food more, and if we take our time to chew and think, we can experience the nuances of flavour and texture. And consequently, we can take the opportunity to eat less yet enjoy more.
    In fact there is one progressive Edmonton coffee shop that has a sign next to the cream and sugar: “Dare you to drink it black”!

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  2. Arya you and I agree on almost everything.

    Here we disagree.

    Our patient populations are not the same as those in the article. The article was looking at consumption of sweeteners in a random patient population, not a weight management population.

    In the random population I wouldn’t be at all surprised to see a Brian Wansink’esque “Health Halo” effect whereupon folks who consumed more artificial sweeteners felt safe to indulge more in food thinking they had the caloric room.

    Regarding our populations however the two studies I know of both suggest that using artificial sweeteners aided weight maintenance efforts.

    The first, Effects of sugar intake on body weight: a review. Obes Rev 2003 4:91-99 concluded,

    “a limited number of relatively short-term studies suggest that replacing (added) sugar by low-energy sweeteners or by complex carbohydrates in an ad libitum diet might result in lower energy intake and reduced body weight. In the long term, this might be beneficial for weight maintenance. However, the number of studies is small and overall conclusions, in particular for the long term, cannot be drawn.”

    The second, a randomized trial, The effect of aspartame as part of a multidisciplinary weight-control program on short- and long-term control of body weight. AJCN 65:409-418 concluded,

    “The aspartame group lost significantly more weight overall (P = 0.028) and regained significantly less weight during maintenance and follow-up (P = 0.046) than did the no-aspartame group. Percentage weight losses at 71 and 175 wk were also positively correlated with exercise (r = 0.32, P < 0.001; and r = 0.34, P < 0.01, respectively) and self-reported eating control (r = 0.37, P < 0.001; and r = 0.33, P < 0.01, respectively). These data suggest that participation in a multidisciplinary weight-control program that includes aspartame may facilitate the long-term maintenance of reduced body weight. ”

    Me – I’m an everything in moderation guy. Calories count and if you can cleave them off without suffering by substituting with some sweeteners, I’d argue that the evidence would in fact suggest that it may be beneficial to a weight management effort. That said, I’d never recommend sweeteners at the expense of enjoying one’s food – case in point and a word of advice for calorie conscious Jewish readers – don’t try to make hamentashen with Splenda.


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