Are diet sodas and artificial sweeteners good for weight loss? Or are they just like sugar and cause weight gain? In this article I’ll get to the bottom of these questions.
What are diet sodas?
For those who don’t know diet sodas are soft drinks where sugar has been substituted with an artificial sweetener or sugar substitutes. The most popular diet sodas are Coke Light, Coke Zero and Pepsi Max. Because diet sodas don’t have sugar they have only negligible amount of calories, and in many cases they don’t have any calories. Artificial sweeteners are anywhere between 30 and 8000 times sweeter than sugar, so they are only needed in very small quantities.
For a nation addicted to sugar diet sodas seem like too good to be true. You can enjoy the sweet taste without having to worry about calories. But not everybody agrees that diet sodas are good for weight loss. Here are some objections raised against them:
- Uncoupling sweetness from calories leads people to eat more sugar and sweets
- Sweet taste increases appetite and hunger, just like real sugar does
- They cause people to eat more
While these objections sound reasonable they are largely refuted by studies.
Studies: Diet sodas good for weight loss
Because artificial sweeteners can help people to overcome sugar addictions and lose weight, they have been studies quite a few times. What those studies show is that artificial sweeteners either have no effect on weight loss or they have slightly positive effect.
In one study researchers asked one group of people to drink about 2 liter of normal soft drinks per day. The other group was asked to drink the same amount of artificially sweetened soft drinks. After 10 weeks the researchers checked to see what had happened. As expected, the group that drank normal soft drinks gained weight. They also had decreased their fat and protein intake. The group that consumed diet sodas lost a little bit of weight, perhaps because decreased their sugar intake.
Other studies have found that:
- Artificial sweeteners don’t cause people to eat more
- People don’t compensate for ‘missing’ calories by eating more later
- Some studies show artificial sweeteners increase hunger levels, other studies show no effect. Despite this, they have no effect on actual calories eaten
So what we can conclude from these studies is that diet sodas and artificial sweeteners can be good for weight loss. There’s no evidence to support the claim they would make people eat more and thus gain weight.
Are there any downsides to artificial sweeteners?
As we’ve seen, diet sodas and artificial sweeteners may help you to lose weight. However the key is how you use them. If you substitute sugar-sweetened soda with diet soda you can save calories and expect to lose weight.
Diet or not, you still have to pay attention to calories. Artificially sweetened ‘diet’ cookies for example may have no calories from sugar, but they still have plenty of calories from other ingredients.
Some people claim that artificial sweeteners can be dangerous. The laundry list of side-effects is as long as California. I’m not sure where these claims come from because pretty much all the safety studies show no negative effects.
- Effects of intense sweeteners on hunger, food intake, and body weight: a review (PDF) – American journal of clinical nutrition
- Intense sweeteners, food intake, and the weight of a body of evidence – Psychology and behavior
- Usefulness of artificial sweeteners for body weight control – Nutrition reviews
- Sucrose compared with artificial sweeteners: different effects on ad libitum food intake and body weight after 10 wk of supplementation in overweight subjects – Americal journal of clinical nutrition
- Intense sweeteners, energy intake and the control of body weight (PDF) – European journal of clinical nutrition
- Are Artificial Sweeteners Safe – WebMD
- Artificial sweeteners: Understanding these and other sugar substitutes – Mayo Clinic