Anyone reading my blog knows that I think food vilification is bad. I think putting foods into “safe” and “unsafe” categories as a general rule is not good, it leads to binging and to obsessive avoidance. I think most foods can just become fuel like any other food. It’s not that I don’t think restriction of some things isn’t good: there’s no way I could say “smoking some cigarettes is fine”. Even eliminating second hand smoke exposure in a town lowers heart attack risks in that town. Yeah, even a little is harmful in some cases. Cigarettes? They are out.
Likewise I think the data is clear that eating more whole foods and more vegetables is better than processed food for health. But I also think that on some levels, there’s room for enjoyment. Let’s say eating a “perfect” diet buys you a little time? I’d take 94 years of cake, health and a lot of exercise over 96 years of no cake. Sorry. Some things are worth it and some degree of eating enjoyable foods probably reduces stress to the point that it’s a wash. Rules like 80/20, 90/10…heck even 70/30 are probably good enough for most people.
Now I blow your minds by saying there’s one “food” that I think you should restrict.
Soda. I just don’t think there’s room for soda as a regular part of a person’s diet. I think if you go the movies twice per year or even a restaurant once per month and enjoy a soda….that’s probably ok. But daily consumption or even 4 x weekly consumption of soda? I think the risks are so great that the benefits to you (enjoyment, caffeine, taste) are rendered into the same category as cigarettes. In fact from a shear weight of research standpoint I don’t think there is any one thing that can compare to soda intake as being modifiably harmful to ones health (after cigarettes). Possibly even more so than obesity.
Speaking of obesity the correlation between obesity and soda consumption is mind boggling to the point of suggesting causation (more on that in a moment). Again, I have an upcoming post on correlation and causation, but a brief summary of the difference I discuss in my facebook feed. It’s clear that soda has been poo-pooed by the health community for a long time, so to find correlation between poor health and soda drinking is not a stretch. It’s actually why some of the studies on eggs are such a problem. Take a food group that for 5-10 years everyone is told is “bad for you” and then 10 years later do a study where people are asked how frequently they ate eggs and look at people’s health outcomes. You might then just measure a group of people that a) ignore health advice b) don’t care/aren’t aware of health advice c) ate more eggs and had worse health. (Well designed studies have suggested that eggs/cholesterol intake probably don’t matter for health, fyi). Soda could be the same.
Having said that the overwhelming magnitude of the data is……overwhelming.
Here’s a study that tried to control for a lot of variables (so eliminating some confounding factors) and found that those drinking one or more soft drinks a day had 1.4 x risk of developing diabetes (which is big in medical research): http://www.ncbi.nlm.nih.gov/pubmed/17646581
Same with diabetes risk across ethnicities in diet soda consumption: http://www.ncbi.nlm.nih.gov/pubmed/19151203
Study of 90,000+ female nurses showed that risk of DMII is increased by 1.83 when drinking one soda per day compared with those drinking 1 per month, those women also showed more weight gain: http://www.ncbi.nlm.nih.gov/pubmed/15328324
This very recent study used the doubly labeled water method to look at people who accurately reported caloric intake and found that drinking sugar sweetened beverages doubled the risk of overweight/obese. In-fact one of their conclusions is that other studies may underestimate the risk of soda drinking because of people underestimating calorie intake. “When limited to true reporters [accurate record of intake], SSB intake significantly increased the risk of being overweight/obese by nearly 4 fold.Conclusion: Underreporting of SSB intake may be attenuating true associations of SSB intake and the risk of being overweight/obese.” http://www.ncbi.nlm.nih.gov/pubmed/23867782
I mean this is a small sampling of the data. It’s hard to find any studies that don’t find this correlation with diabetes, obesity and/or early death.
So again, it’s hard to show CAUSATION. Maybe if you eat and live like a non-soda drinker from one of these studies but also drink soda, maybe you are ok….except I have a theory. A theory on causation. I have independently noticed a finding of low magnesium levels in chronic soda drinkers. In my area there is a large population of overweight middle age people who drink soda daily (usually more than one- they don’t drink any coffee or tea) and I’ve found that they frequently have diabetes/pre-diabetes and low magnesium. I have a theory that the inorganic phosphate, which is known to be very hard on the kidney, was directly or indirectly causing magnesium wasting in the kidney. I can only find bro-science level information to confirm my suspicions that the two are directly linked (inorganic phosphate from soda and magnesium). I will continue my search to find good science to suggest this causation may be true. But what I do know is that there’s something to this association.
Magnesium is sooooooo important. In fact it’s directly involved with both sugar metabolism and insulin sensitivity. In fact magnesium supplementation can potentially increase insulin sensitivity! This is covered so well by Stephen Guyenet, I’ll send you to his great site and this post here.
So what if soda is actually harmful and bad for health not because of the sugar load, but because of direct effects of magnesium wasting which leads to decrease insulin sensitivity (and eventually diabetes)? For me that’s enough to recommend not drinking the stuff. Too much correlation and the possibility of causation. There’s also some mixed evidence that liquid calories don’t cause as much satiety, which could be a big issue also. Again this data is very mixed, so hard to know if that’s a factor. There may be some gender differences in that women may get less satiety from liquid calories then men.
I’ve been recommending against soda consumption while recommending ETF. Again, most people are drinking it for caffeine, which can be obtained from coffee or tea in a much safer and possibly even health benefiting way. Likewise if one is religiously forbidden from coffee/tea consumption, then I suggest looking at the lifestyle that is forcing you to drink soda to stay awake. In fact we should all take a hard look at why we need caffeine so much to stay awake. I think someone is much better off eating a cookie as a snack (if you want something tasty and delicious or quick calories) then a soda.
So let me circle back around to causation and correlation. All we really have is correlation here, despite my theory. If you are metabolically healthy, eat a lot of leafy greens, nuts, and halibut, relatively normal weight (BMI under 30), and fit- then my recommendation to avoid soda probably doesn’t matter for you. You aren’t showing any signs of the things I’m worried about, specifically insulin resistance or obesity. But if you have diabetes, PCOS, obesity, poor metabolic health….oh man this is low hanging fruit here people. If you are unhealthy but say “they’ll pry my coke from my cold dead hands”….then you really, really sound like a tobacco addict or alcoholic. I find that addicts frequently have just said “screw it, I choose unhealth”. We should all be striving for good health.