The other day I was over to one of the coffee shops close to our gym. I'm late to the coffee party but I definitely enjoy an americano once or twice a week.
Anyways there were a couple of younger women in line in front of me. And their conversation went something like this:
Woman 1: I think I'm going to do an apple cider vinegar cleanse before Christmas. I can do it for a week now before Christmas and lose up to 7 pounds. Woman 2: Yeah, I've heard of that one as well. Why would you do it before Christmas? 1: I typically gain 5-7 pounds over the holidays so if I lose the weight before I can enjoy the holidays guilt-free and be at the same weight I am now. 2: Cool. Let me know and I'll do it with you. 1: Ok I'm going after work to (local health food store) to pick up the cleanse kit. Why don't you come as well? 2: Sounds good. Let's do it. ***
Of course I had to bite my tongue while in line.
What I would have to like to have shared with these young women is that cleanses just don't work. I've written about cleanses and detoxes before. And a review of the literature (1) on detoxes and cleanses stated:
..no randomized controlled trials have been conducted to assess the effectiveness of commercial detox diets in humans. But unfortunately the blog of strength and conditioning coach is going to get less traction than the headlines of supermarket tabloids.
Most people would say they use cleanse or detox to get rid of toxins or to lose weight. The young women in the coffee shop are a perfect example of this.
The problem with this is the 'weight loss' attributed to cleansing is typically due to caloric restriction and dehydration. If I go an entire week drinking only water, apple cider vinegar, lemon, ginger or ...I won't be getting the caloric (or nutritional) equivalent of a whole food diet. And the dehydration typically is associated with the reduction or elimination of carbohydrates from the diet. If I cut the morning toast not only am I eliminating over 300 calories from my intake I'm also cutting 3 grams of water for every gram of carbohydrate. So the pieces of bread would normally provide 30 grams of carbs and another 90 grams of water when digested.
So we eat a little less and pee out the water normally required to digest carbs. We're not really get leaner or healthier.
And if you wanted to see how this impacts performance try setting a personal best for a 5 km run and see how that goes.
But it gets worse.
I remember a colleague mentioning that after a carbohydrate restriction the body will soak up more of the nutrients that it has been missing. The analogy was a dried out sponge left in the sun will soak up more water than a soggy sponge. I'm not aware of any research showing this but the example intuitively makes sense.
Potentially the biggest problem with cleansing, if used for a weight loss goal, is that liquids tend to less satiating than solids (2). Most cleanses and detoxes involve the reduction, or elimination, of solid food for a period of time. We drink a special concoction, take our required supplements and/or colonics, before dropping the weight.
Imagine a big bowl of fruit in front of you. And you were going to eat a banana, an apple, a peach, half a cup of strawberries and a half cup of blueberries. Very few people would be able to eat this much fruit. But looking at the ingredients list of many commercial smoothies have this much fruit and maybe more.
While most of the research shows solid food to be more satiating than liquids there some studies that show liquids to be more effective at filling us up (3). These studies used soups as the liquid instead of smoothies or another liquid that we could drink.
At so there is the question as to whether satiety is affected by the act of chewing. Does the act of chewing on food impact the brain, enzymes and digestive process enough to effect safety? This might make sense if we consider the example with soups. Often times soups can be hearty and include a protein, vegetable or noodle that requires chewing in order to eat.
Solid food also takes longer to consume than a liquid meal. You could drink something in as little as a few minutes. It's pretty hard to finish a solid food meal in as little an amount of time. And on the flip side a solid food food meal could take over an hour when it involves conversation and interaction with others. It's pretty hard to stretch out a liquid meal that long.
There is also the expectation that a solid meal will be more satiating. Even if calories were matched there's no way we would expect a drink to fill us up as much as a steak.
It's interesting to note that the studies didn't notice a difference when the test subjects were lean or obese, active or sedentary.
Going forward during the Christmas season don't use cleanses or detoxes as a weight loss strategy. In the long run all you'll lose is a few dollars from your wallet and some water weight. And be particularly aware of relying on liquid nutrition as you won't feel as full and may over eat at parties and holiday gatherings.
References
- A. V. Klein and H. Kiat. Detox diets for toxin elimination and weight management: a critical review of the evidence 2014. J Hum Nutr Diet. 2015. 28(6):675-86.
- Zhu Y, Hsu WH and Hollis JH. The effect of food form on satiety. Int J Food Sci Nutr. 2013;64(4):385-391.
- Clegg ME, Ranawana V, Shafat A, Henry CJ. Soups increase satiety through delayed gastric emptying yet increased glycaemic response. Eur J Clin Nutr. 2013;67(1):8-11.