A few weeks ago our friend Colby Vorland of Nutritional Blogma emailed me an article titled “The Chocolate Milk Diet“, which he had come across via Twitter. The article (which was written and published last year by the editor-in-chief of Men’s Health and Women’s Health David Zinczenko) got both of our BS detectors going, and we thought it would be a good idea to tag-team a post deconstructing the arguments in the original article (Given that Colby is far more knowledgeable about nutrition than I am, the lion’s share of this post – and all of the good parts - is his). You can also read the post on his blog, which is definitely worth checking out if you’re not already. Enjoy!
Usually I (Colby) ignore these kind of things, but the article was so nonsensical that I felt it needed to be critiqued, especially considering the huge audience it probably reached and influenced (it received over 2,000 Facebook likes on Yahoo alone! And think of the reach of the Men’s Health magazine). Articles like this really do health professionals a disservice, as they spread bad nutrition information around like wildfire; it is no wonder people don’t know what advice to follow. And of course many other health and fitness organizations including Goodlife, Running Room, and Livestrong.com are also on the chocolate milk bandwagon (the latter two are proudly mentioned in this press release from the Dairy Farmer’s of Canada), such that it is almost impossible to avoid the the chocolate milk media machine. In the face of a barrage of such one-sided information, we can sometimes benefit from a reminder that, as Yoni Freedhoff puts it, “milk is not a magic fairy food that confers the health of immortal unicorns”. So here is our passage-by-passage rebuttal to The Chocolate Milk Diet (emphasis ours).
“Imagine if everything you needed to know about weight loss, you learned in kindergarten.”
Most of us continued learning after kindergarden, Mr. Zinczenko. (OK, no more zingers, only science)
“Well, if your teacher gave you chocolate milk as a lunchtime treat, she was (unknowingly) giving you one of the most powerful weight-loss tools in the nutritional universe. Turns out this childhood staple may be the ideal vehicle for your body’s most neglected nutritional needs. Each bottle delivers a package of micro- and macronutrients that can help you shake off body flab and replace it with firm muscle. And when you served it ice-cold, the creamy sweetness flows across your tongue with all the pleasure of a milk shake. Yum.”
Sure, chocolate milk tastes good- the lowfat (that Zinczenko recommends) version has about 25 grams of sugar per 8 oz. serving (1) (Zinczenko recommends 3 servings per day), twice as much as 1% white. Per glass, the Calorie content is about 158, giving you about 474 Calories per day, just from chocolate milk (1). Let’s see how he thinks adding chocolate milk will help you lose weight:
“That’s the crux of what I’m calling “The Chocolate Milk Diet,” which isn’t a diet at all. It’s essentially three eight-ounce servings of chocolate milk consumed at key points throughout your day: one when you wake up, a second before you exercise, and a third directly after your workout. Or, if it’s your day off, just pattern them for morning, afternoon, and night. Sounds good, right? It is, and that’s why it’s so easy. But is this a free ticket to eat as much fried chicken as you want throughout the rest of the day? Unfortunately not, but alongside a healthy diet, it can help you drop lots of belly fat fast. Here are the four reasons why:
Secret #1: The Calcium Effect
Researchers have known for years about the role that calcium plays in building strong bones, but a more recent development deals with they way it affects your belly. A series of studies have shown that calcium can actually impede your body’s ability to absorb fat, and when researchers in Nebraska analyzed five of these studies, they were able to estimate that consuming 1,000 mg more calcium can translate to losing nearly 18 pounds of flab. What’s more, other studies have shown that dairy foods offer the most readily absorbable calcium you can find. Knock back three servings of brown cow and you’ll reach that crucial 1,000 mg threshold. At that point, any other calcium that you eat or drink is a bonus.”
Zinczenko refers (vaguely of course, who is going to take the time to look any of these up, right?) to 1 review paper from 2000 (2). His claim, however, that you can lose nearly 18 pounds of fat with 1,000 mg of calcium is not supported by this paper. Even in the abstract it states that: “Estimates of the relationship indicate that a 1000-mg calcium intake difference is associated with an 8-kg difference in mean body weight and that calcium intake explains 3% of the variance in body weight.” This result is estimated from statistical analysis of 4 observational studies in the review.
Since this was published, more research has been done in this area. Luckily, a new meta-analysis on randomized controlled trials with calcium and weight was just published by Onakpoya and colleagues (18). Of 24 trials, they included 7 in one analysis (all of which were on overweight or obese subject- important to keep in mind), and concluded that calcium supplementation for at least 6 months reduced body weight by only 0.74 kg, with no relationship between dose and weight loss. The authors note that “the clinical relevance [...] is debatable.” Most trials are small thus it will be important for larger studies to see if this effect is an artifact or not. Note that this is calcium per se, independent of the calories in milk. Also note that they needed to exclude studies from their analysis because of poor design and/or result reporting. It is necessary to survey all research in an area to get a more accurate picture instead of cherry picking results like Zinczenko tries to do to support his ideas. Notably, this meta-analysis was supported by Heaney in an editorial, who has done a lot of the research in this area (and was involved in the 2000 review that Zinczenko cited).
Another recent meta analysis (19) published in in 2009 supports the idea that dairy calcium may prevent fat absorption (e.g. you poop out more fat; this is one mechanism in which calcium may exert a small effect on weight loss), although the magnitude of this effect is pretty tiny. From the review paper:
We estimated that increasing the dairy calcium intake by 1241 mg day-1 resulted in an increase in faecal fat of 5.2 (1.6–8.8) g day-1.
So how much milk would you need to drink in order to get that much calcium? 1 cup of 1% white milk has 290 mg of calcium, which means that you would need to drink roughly 1 L (4.4 cups) in order to get 1290 mg. It should be pointed out that this will mean ingesting more than 400 calories, all so that you can hopefully poop out an extra 81 calories of fat (there are 9 calories per gram of fat). Now if you were to drink chocolate milk as the Men’s Health article suggests, you would need to drink nearly 700 liquid calories in order to excrete 81 calories! Clearly, the math doesn’t quite add up.
While there is biological plausibility that calcium may have a small effect on weight (other potential mechanisms have been identified as well), Zinczenko’s logic does not agree with research and common sense.
“Secret #2: The Vitamin D Factor
All the calcium in the world isn’t going to help you if you don’t get a good dose of vitamin D to go with it. That’s because vitamin D is responsible for moving calcium from your food to your body, which means if you’re running low on D, you’re probably also missing the calcium you need to stay slim.”
Yes, vitamin D promotes calcium absorption, but you need a lot more than what you can get from milk- see below.
“Other symptoms of the D deficiency are weak muscles, easily breakable bones, and depression—not a great combo for success.”
The effect of vitamin D on muscle function has been demonstrated in elderly populations (and not all evidence shows vitamin D helps (3), differences may be explained by vitamin D dose or type, baseline or final 25(OH)D concentrations (which signify vitamin D status) thus plenty remains to be answered), but in younger populations we cannot yet say this with certainty except for extreme vitamin D deficiency.
“Now here’s why this is significant: Most experts agree that the average American isn’t getting enough D. Some estimate that only half the population is meeting the requirement and one study published in the journal Pediatrics found that 70 percent of American children had low levels of D in their diet. The thing is, your body makes vitamin D naturally when you expose your skin to sunlight, but most people spend too much time indoors to benefit. And intentionally spending more time in the sun could put you at risk for skin cancer. The solution? Drink up. Chocolate milk, like most milk, is fortified with vitamin D.
Most people are insufficient or deficient in vitamin D, true. While I (Colby) haven’t studied the sunlight/cancer link to a significant degree, it doesn’t take much sunlight exposure for the skin to produce D. Season, skin pigment, time of day, age, geography, and other factors will affect this, but if you spend time outside sensibly (avoid sunburn), it is possible to produce a dose equivalent to 1000 IU of oral vitamin D(3) in 5 minutes with the skin from your face, neck, hands, arms, and legs exposed (16). Most people will require supplementation to maintain vitamin D concentrations that are considered “ideal” (based on research (17), likely above ~75 nmol/L) as sunlight exposure is limited in most developed populations.
Zinczenko’s vitamin D “solution” is to get it from milk. Food sources are generally poor sources of vitamin D. On average, for example, males 19-30 years old consume 230 IU per day from food in the U.S. (4). Chocolate milk contains approximately 108 IU per 8 oz. serving. Zinczenko’s recommendation would give you only about 330 IU more vitamin D per day- and that is assuming you don’t replace any milk you currently drink with chocolate. The combined ~560 IU per day is not nearly enough vitamin D for optimal calcium absorption, for example. Consider that some of the top vitamin D researchers recommend 1500-2000 IU of supplemental vitamin D per day for adults to maintain vitamin D (25(OH)D) concentrations above 75 nmol/L (and this is just maintenance- if you begin deficient you will need more to reach this level) (17). A study by Heaney et al. (5) found that the optimal vitamin D concentration for calcium absorption in postmenopausal women may be around 80-90 nmol/L, and enhanced absorption has been demonstrated in healthy men as well (6). For more references see (7, 17). Age, weight, and other factors influence the amount of vitamin D needed to increased vitamin D concentration, but for most people who do not receive much sunlight exposure, the dose needed will likely be well above 1,000 IU per day, (more than) twice what Zinczenko’s milk protocol and regular food intake can provide.
“One caveat here: Drink 1% chocolate milk. Vitamin D won’t work without a little fat to help break it down. You want to skip the whole milk, too, as it has too many calories to make it a regular habit. The best option is 1%, or low-fat chocolate milk. It has the fat you need to absorb crucial vitamins, yet at three cups a day, it will save you 120 calories over whole milk.”
Fat isn’t needed to help vitamin D “break down”- but assuming he means for improved absorption, it is unlikely in this case to have a significant effect. As far as I can tell, this is still controversial (8), however a recent study found that supplementing with a large meal improves absorption (9). Top researchers state that “it does not require dietary fat for absorption” (17). In any case, there are less than 3 grams of fat per 8 oz. glass of lowfat chocolate milk, likely making this a negligible contribution anyway.
“Secret #3: The Endurance Boost
If you want to lose the gut, you’ve got to exercise—no surprise there. But here’s a fact that’s not so obvious: Drinking chocolate milk can improve your gains. In a study published in The International Journal of Sport Nutrition and Exercise Metabolism, subjects given chocolate milk before hopping on the stationary bikes were able to ride 49 percent longer than subjects given a generic carbohydrate-replacement beverage. And on top of that, they pedaled even harder. Total work performed by the chocolate-milk group was greater than the work performed by subjects drinking carbohydrate-replacement drinks or electrolyte-fortified sports drinks.”
This study (20) was reviewed by Peter Janiszewski here (full text here). It showed that chocolate milk or a beverage with similar macronutrient ratios to chocolate milk (Endurox) were superior to Gatorade, which has less than half the carbohydrates as either, no protein, and less than a third of the calories! Is is no surprise that both chocolate milk and Endurox (which Zinczenko conveniently doesn’t mention) were superior. But Zinczenko explains the results like this:
“The reason? Milk has naturally occurring electrolytes that keep you hydrated—more hydrated then water, in fact, which I revealed recently on my Twitter account—and its natural sweetness helps push more energy into your muscles. Another study from 2009 found similar results, but it went one step further by asking participants which beverage they thought tasted better. Not surprisingly, 100% chose chocolate milk.”
Gatorade also has electrolytes. How do the mystical-sounding “naturally occurring electrolytes” in milk hydrate you better than water? There are a lot of myths surrounding electrolytes, especially with regard to cramps (while not directly relevant to what Zinczenko claims, I recommend reading the great articles at SportsScientists.com (10) and SweatScience.com (11) if this interests you).
As far as milk pushing “more energy into your muscles” because of “its natural sweetness,” that makes no sense, unless he means it more quickly replenishes glycogen stores because of the simple sugar content. This shouldn’t be a concern unless you are an athlete on an intense training regimen, and clearly Zinczenko’s article was not aimed at this population.
For me personally (Travis), this is by far the biggest problem with Zinczenko’s argument, and others like it. Just as I don’t doubt that calcium may promote (modest) fecal fat excretion, I also believe that chocolate milk is a pretty good post-workout beverage for elite athletes focused on maximizing their training. And yet most of us are not elite athletes. For people who are attempting to manage their weight, I would argue that consuming several hundred non-satiating liquid calories (e.g. a bottle of chocolate milk) to achieve some sort of “performance benefit” just doesn’t make sense whatsoever.
While chocolate milk may be better than plain carbohydrate sources for athletes, it is not worth the excessive calories for those trying to lose weight. Also, not refueling with carbohydrates post workout is best for increasing insulin sensitivity (12), which may be better for non-athletes, though further (long term) research is needed in this area.
“Secret #4: The Protein-Body-Weight Connection
Want to know the secret to staying thin? You need more muscle. That’s because muscle burns more calories than fat, so for every new muscle fiber you create, your resting metabolism receives another surge of fat-torching energy.”
Another person touting the muscle-metabolism theory. In reality, on average the amount of calories per day burned for every extra pound of muscle is only about 6 (13) or a little less than 5 (14). So if you were to convert 10 lbs of fat into 10 lbs of muscle – certainly nothing to sniff at – you would only be burning an additional 50-60 calories per day. For a 200lb man, that’s the equivalent of 8 minutes of walking at a normal pace. Yes, calories can add up over time, but that’s still not a tremendous amount of calories for a pretty large increase in muscle mass. And let’s not forget that even gaining fat tissue will increase metabolic rate by about 2 calories per pound per day. Of course appetite compensates and you consume more to sustain it, but the same goes for muscle mass! You need a calorie deficit to lose weight, period.
“And chocolate milk can help you do that. Researchers have determined that the ideal protein load for building muscle is 10 to 20 grams, half before and half after your workout. How much protein will you find in low-fat chocolate milk? Eight grams per cup. (That means one serving before your workout and one serving after will give you a total of 16 grams of highly effective whey protein—a perfect serving.) Add that to the extra cup you drank first thing in the morning and you’re looking at a turbocharged metabolism that keeps you burning calories all day long.”
“Researchers have determined…” which researchers, what research? You can’t establish an ideal load for stimulating protein synthesis unless you state the composition. Leucine, an amino acid in protein, is the critical stimulator of protein synthesis. Sources rich in leucine need a lesser amount. I don’t recall ever seeing research concluding that a 5-10 gram dose of protein at a time is optimal- in fact plenty of studies use doses higher than this. Consider for example, a study from 2009 (15) that found 20 grams of egg protein maximally stimulated protein synthesis after resistance training, whereas doses of 5 grams and 10 grams were suboptimal. The dose will ultimately depend on factors such as total muscle mass, age, whether you exercised fasting, etc. Zinczenko is just making things up.
In conclusion, scientific evidence does not support any of Zinczenko’s “secrets,” and an extra ~475 Calories from chocolate milk per day is likely to make weight loss difficult, and quite possibly cause weight gain if other calories are not carefully accounted for.
1. U.S. Department of Agriculture, Agricultural Research Service. 2010. USDA National Nutrient Database for Standard Reference, Release 23. Nutrient Data Laboratory Home Page, http://www.ars.usda.gov/ba/bhnrc/ndl
2. Davies, K.M. et al, 2000. Calcium Intake and Body Weight. Journal of Clinical Endocrinology & Metabolism, 85(12), pp.4635-4638. Available at: http://jcem.endojournals.org/cgi/doi/10.1210/jc.85.12.4635
3. Rejnmark, L., 2010. Effects of vitamin D on muscle function and performance: a review of evidence from randomized controlled trials. Therapeutic Advances in Chronic Disease, 2(1), pp.25-37. Available at: http://taj.sagepub.com/cgi/doi/10.1177/2040622310381934
4. Moore, C. et al., 2004. Vitamin D intake in the United States. Journal of the American Dietetic Association, 104(6), pp.980-3. Available at: http://www.ncbi.nlm.nih.gov/pubmed/15175600
5. Heaney, R.P. et al., 2003. Calcium absorption varies within the reference range for serum 25-hydroxyvitamin D. Journal of the American College of Nutrition, 22(2), pp.142-6. Available at: http://www.ncbi.nlm.nih.gov/pubmed/12672710
6. Heaney, R.P. et al., 1997. Calcium Absorptive Effects of Vitamin D and Its Major Metabolites. Journal of Clinical Endocrinology & Metabolism, 82(12), pp.4111-4116. Available at: http://jcem.endojournals.org/cgi/doi/10.1210/jc.82.12.4111
7. Heaney, R.P., 2011. 25-Hydroxyvitamin D and calcium absorption. The American journal of clinical nutrition, 93(1), pp.220-1; author reply 221. Available at: http://www.ncbi.nlm.nih.gov/pubmed/21068356
8. Grossmann, R.E. & Tangpricha, V., 2010. Evaluation of vehicle substances on vitamin D bioavailability: a systematic review. Molecular nutrition & food research, 54(8), pp.1055-61. Available at: http://www.ncbi.nlm.nih.gov/pubmed/20425758
9. Mulligan, G.B. & Licata, A., 2010. Taking vitamin D with the largest meal improves absorption and results in higher serum levels of 25-hydroxyvitamin D. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research, 25(4), pp.928-30. Available at: http://www.ncbi.nlm.nih.gov/pubmed/20200983
10. Tucker, R. & Dugas, J. (Website) Available at: http://www.sportsscientists.com/search/label/electrolytes
11. Hutchinson, A. (Website) Available at: http://sweatscience.com/?s=electrolytes+hydration
12. Vorland, C. Should post exercise meal consumption differ for athletes compared to casual exercisers? (Blog post) Available at: http://recomp.com/blogma/2010/02/should-post-exercise-meal-consumption-differ-for-athletes-compared-to-casual-exercisers/
13. Gallagher, D. et al., 1998. Organ-tissue mass measurement allows modeling of REE and metabolically active tissue mass. The American journal of physiology, 275(2 Pt 1), pp.E249-58. Available at: http://www.ncbi.nlm.nih.gov/pubmed/9688626
14. Wolfe, R.R., 2006. The underappreciated role of muscle in health and disease. The American journal of clinical nutrition, 84(3), pp.475-82. Available at: http://www.ncbi.nlm.nih.gov/pubmed/16960159
15. Moore, D.R. et al., 2009. Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men. The American journal of clinical nutrition, 89(1), pp.161-8. Available at: http://www.ncbi.nlm.nih.gov/pubmed/19056590
16. Engelsen, O., 2010. The Relationship between Ultraviolet Radiation Exposure and Vitamin D Status. Nutrients, 2(5), pp.482-495. Available at: http://www.mdpi.com/2072-6643/2/5/482/
17. Holick, M.F. et al., 2011. Evaluation, Treatment, and Prevention of Vitamin D Deficiency: an Endocrine Society Clinical Practice Guideline. Journal of Clinical Endocrinology & Metabolism. Available at: http://jcem.endojournals.org/cgi/doi/10.1210/jc.2011-0385
18. Onakpoya, I.J. et al., 2011. Efficacy of calcium supplementation for management of overweight and obesity: systematic review of randomized clinical trials. Nutrition reviews, 69(6), pp.335-43. Available at: http://www.ncbi.nlm.nih.gov/pubmed/21631515
19. Christensen, R. et al., 2009. Effect of calcium from dairy and dietary supplements on faecal fat excretion: a meta-analysis of randomized controlled trials. Obesity reviews : an official journal of the International Association for the Study of Obesity, 10(4), pp.475-86. Available at: http://www.ncbi.nlm.nih.gov/pubmed/19493303
20. Karp, J.R. et al., 2006. Chocolate milk as a post-exercise recovery aid. International journal of sport nutrition and exercise metabolism, 16(1), pp.78-91. Available at: http://www.ncbi.nlm.nih.gov/pubmed/16676705
Onakpoya, I., Perry, R., Zhang, J., & Ernst, E. (2011). Efficacy of calcium supplementation for management of overweight and obesity: systematic review of randomized clinical trials Nutrition Reviews, 69 (6), 335-343 DOI: 10.1111/j.1753-4887.2011.00397.x
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