A couple of weeks ago I asked for people to share their nutrition questions with me and I want to thank those of you who did so. As for the rest of you ... (cue scary music) ... still feel free to ask! :)
The first question I received was a about diet products, specifically diet beverages such as diet colas (eg. Diet Coke). This is a common question and sadly, there is no simple answer at this point. What I can do is give you a brief summary of what we know, and then I can lay out a discussion about these controversial beverages. Be forewarned - I will be discussing aspartame primarily here.
Ok, let's get started:
What We Know (or at least think we know ...):
About weight gain and food addiction:
Large epidemiological studies (ones where they look at trends in a specific group of people without really interfering in their lives) have shown some evidence that people who drink diet drinks tend to gain more weight than those who don't drink them. However, the evidence is rather weak, and researchers aren't so sure that they can blame diet drinks, the sweeteners (eg. aspartame), or something else for the weight gain.
Some studies in rats (because it's easier to force a rat to eat and drink certain things than it is with people) have shown that sweetened beverages (such as diet drinks) increase appetite and food intake. This has caused some researchers to believe that sweet things make you crave more sweet things, which makes for a sort of food or sweets addiction.
I must confess that I didn't spend a lot of time reading up on this aspect of the sweetener debate, but here's what I have: if you consume obscene amounts of artificial sweeteners (such as aspartame), it may cause cancer. Some studies have focused on the liver and liver cancer in mice.
How much is safe?:
Health Canada states (about aspartame) that "there is no evidence to suggest that the consumption of foods containing this sweetener, according to the provisions of the Food and Drug Regulations and as part of a well-balanced diet, would pose a health hazard to consumers."
Health Canada has also given aspartame an ADI (Acceptable Daily Intake) of 40 mg per kg body weight per day. That means that a 150-pound person could have approximately 2700 mg of aspartame a day (one can of diet pop has about 200 mg of aspartame). This means that if your only source of aspartame was diet pop, you could have approximately 13 cans of diet pop a day without expecting any problems (related to the aspartame at least!). That's A LOT of diet pop.
As a dietitian, there are some questions that come to mind when I discuss sweeteners with clients.
1. Why diet?
Why are you choosing a diet drink? Is it because you want to lose weight? Because you have diabetes? Because you like the taste?
If you're trying to lose weight, it's true that diet beverages have fewer calories than the regular versions of those drinks, but there are other calorie-free beverages to choose from.
If you have diabetes, it's true that many sweeteners won't cause your blood sugar to go up, but again, there are also other options available to you.
If you choose diet drinks because you like the taste, well, I guess that makes good sense. Where else are you going to find that flavour?
2. What type of diet beverage are choosing?
Are you having Diet Coke (or Diet Pepsi or any other type of diet pop)? Is it calorie-free juice? Or calorie-reduced juice? Is it Crystal Light (or something similar)?
If you're having pop, why? Is it the carbonation you like? Is it the flavour of that type of pop?
If you're having calorie-free juice or Crystal Light, why? Are you just looking for something calorie-free with some flavour?
3. What do you eat when you have diet beverages?
Do you eat with your diet beverage? Or is your diet drink a snack of its own?
If you're eating with your diet drink, what types of food are you eating? I suspect you're not having an apple and almonds with it or a slice of whole-grain toast with natural peanut butter. Am I right? And why is that? (Hint: think about yesterday's post.)
Maybe you're having your diet pop as your drink with a meal. What other good drink options might you be snubbing in favour of the diet pop?
If the diet drink is a snack of its own, we may have a problem. Diet drinks don't offer much in the way of calories, which is why they are popular with those who want a sweet drink with few calories. Therefore, they don't make a good snack. They don't give you any nutrients that your body needs. After all, your stomach tells you its hungry because it wants to feed your body some good old fashioned nutrients, not because it wants a make-work project. Right? Better off to go for some real food.
Take Home Message:
In moderation (like anything else), diet drinks, aspartame (and the like) are probably fine. It's not likely that you'll sprout an extra head or develop cancer solely because you had a Diet Coke once a day. However, it's important to look at why you're turning to diet drinks and to decide if they're your best option. After all, our bodies are more than 50% water, not Diet Coke. Just sayin' ....