What would good nutritional advice look like?

Maybe like this.

This is one of several charts in ‘Nutrition for Swimming’, an article in the International Journal of Sports Nutrition and Exercise Metabolism, written by a team of researchers from the UK, Norway, and Australia. This table acknowledges the different levels of exertion and varied demands of training. It then matches nutritional advice to those demands, with an emphasis on performance.

Or like this.

This powerpoint, from a physician at UCLA responsible for improving the performance of the university’s athletes, acknowledges the individual nature of nutritional needs, and the importance of goals in establishing eating patterns. Also, this presentation flags UNDEREATING as the main nutritional concern for athletes.

And this is pretty good.

This table – from the consensus statement released by the American College of Sports Medicine along with the main dietitians’ associations in the US and Canada – does something novel. It recognizes that evidence in nutritional research is evolving, and some evidence is better than other evidence. They rate their confidence in the evidence, and then explain why it matters.

Simply put, good nutritional advice for teenage endurance athletes in general, and swimmers in particular, has the following characteristics:

  • Athletic goals drive the nutritional advice.
  • Guidance is specific to the athletes. Nutritional concerns that relate primarily to people in middle-age and later are not raised.
  • The difficulty of consuming enough food is acknowledged.
  • As such, nutritional guidelines for consumption of macronutrients and calories are mostly expressed as minimums, not maximums.
  • The threat to the athlete’s health that comes from undereating is emphasized repeatedly.
  • The threat to the athlete’s performance that comes from undereating is emphasized repeatedly.
  • The dangers of fat restriction (or restriction of any macronutrient) are emphasized repeatedly.
  • None of the macronutrients are demonized or discussed in a manner that suggests they are toxic or dangerous.
  • The different nutritional needs of men and women are discussed.
  • The seemingly extreme diets (in terms of quantity consumed) of elite athletes are openly discussed. These nutritional approaches are not disparaged or dismissed as unhealthy.
  • The evidence for nutritional recommendations is candidly evaluated. Where the evidence is truly inconclusive, recommendations are not offered.
  • The advice is kept as simple as possible, but not simpler than that.

I mean, is that so hard?

USA Swimming gives bad advice directly to swim coaches, Part 2

If you Google ‘USA Swimming what should I eat?’ you’ll get this slideshow. This is the second post in which we try to make sense of the nutritional advice USA Swimming gives to swim coaches.

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Slide 18. ‘Become a Nutrition “Expert” in 45 Minutes!’ [Slide show title], How to Talk to your Athletes about Nutrition – USA Swimming [Title listing on USA Swimming site]. Presented by Jay Chambers, Sports Performance Consultant. (c) USA Swimming. 2017.

This is slide 18. And it is a mess.

The first sentence is gibberish. Foods are miscategorized, and classified according to their moral worth. This is far below the standards we ought to expect from USA Swimming.

These categories are nonsense. White bread and wheat bread, white rice and brown rice, white pasta and whole grain pasta, oatmeal and biscuits are mostly polysaccharides, otherwise known as ‘complex carbohydrates.’ All the foods listed here provide more complex carbohydrates than simple carbohydrates except for cane sugar (a disaccharide), soda (sweetened with disaccharides), juice (naturally containing a lot of disaccharides and the monosaccharides glucose and fructose), nuts and seeds.

Nuts and seeds should not be on this list at all. Nuts and seeds are not significant sources of carbohydrate, simple or complex. In a 100 calorie serving of almonds, about 80 calories come from fat, about 15 calories from protein and maybe 5 calories come from carbohydrates (of which half are simple carbohydrates). In 100 calories of sunflower seeds, you’d get 82 calories from fat, 9 calories from protein, and 9 calories from carbohydrate (6 calories of complex carbohydrates, 3 calories from simple carbohydrates).

Bottled sauces. Really? ‘Bottled sauces’ gets its own mention? The sugar in ketchup or barbecue sauce is not a nutritional matter of significance to adolescent endurance athletes.

‘Bad carbs’ are GOOD for adolescent endurance athletes.

  1. Pure energy intake. For adolescent endurance athletes, quantity comes first. And the quantity requirements can be hard to meet. If adding in cakes, biscuits, soda, and juice is the only way to ensure consumption of adequate energy, do it. Also consider ice cream, cookies, doughnuts, cupcakes, whipped cream, chocolate syrup, and candy.
  2. Fueling during intense exertion (whether practice or meets). Simple sugars – cane sugar, table sugar, sucrose, disaccharides, whatever you call it – are the most practical and useful fuel to consume while exercising or competing. Sugar (either sucrose and/or high fructose corn-syrup) is the energy source in sports drinks and gels. Don’t shy away. Sucrose is half glucose and half fructose. High fructose corn syrup is 55% fructose, 45% glucose. When combined, glucose and fructose provide more usable energy during exertion than glucose alone or fructose alone or anything else so far identified. Complex carbohydrate sources release energy more slowly precisely because they are ‘complex’, so they are good if you have time to digest and you want the energy pay-off later on. If you need energy now, eat sugar.
  3. Recovery and restocking glycogen after exercise. When you eat white bread, white pasta and white rice, your body efficiently converts it to glucose with little waste (fibre). Some of that glucose is used for immediate energy and the rest is converted to glycogen. The glycogen is then shunted off to the muscles and liver for later use during high-intensity exertion. It is hard to beat refined grains for convenience, palatability, and efficiency in restocking glycogen stores.

Fibre: Fibre is the only thing that unites the foods listed in the ‘Good Carbs’ column. Middle-aged office workers on diets love fibre. Fibre, by definition, cannot be digested and used for energy. It moves deliberately through the stomach and digestive tract. You can eat smaller amounts of high-fibre foods and feel more full. If you are dieting and trying to reduce the overall energy available in your body (lose fat tissue), fibre is your friend.

If you are an adolescent endurance athlete, fibre is NOT your friend. Whole grain bread, whole wheat pasta and brown rice have more fibre (about 2-3 times as much), and thus less digestible carbohydrate, than equivalent amounts of more refined grains. Gram for gram, whole grain bread and pasta and brown rice (compared to more refined ‘white’ versions) will make adolescent athletes feel more full (bad) while providing less glucose for glycogen restoration (also bad).

Let’s do one more slide before taking a break. OK, slide 19, ‘Functional Fueling: Protein’ Among other things we are told that protein:

Aids absorption of carbohydrates

No, it doesn’t. From ACSM 2016: Compared to ingestion of carbohydrate alone, coingestion of carbohydrate plus protein together during the recovery period resulted in no difference in the rate of muscle glycogen synthesis.

More later.

USA Swimming gives bad advice directly to swim coaches, Part 1

If you Google ‘USA Swimming what should I eat?’ you’ll get this slideshow.

The slideshow was prepared and presented by a consultant hired by USA Swimming to provide nutritional advice to coaches at clinics held around the country.

This slideshow starts with uncontroversial and agreeable advice about nutrition and competition. Prepare Your Body Nutritionally for Training and Racing…Fueling must be similar to endurance athletes… the 24/7 Athlete.

But what follows is a series of statements that contradict established biological facts and basic consensus, nutritional advice for athletes like the 2016 statement by the American College of Sports Medicine, the Academy of Nutrition and Dietetics (USA), and Dieticians of Canada (ACSM 2016) .

Let’s start on a positive note.

Swimmers’ training regimen is comparable to tri-athletes, long-distance runners and cyclists. High volume, with various intensities.

Sounds right. On the next slide we read:

Primary fuel source > Carbohydrates

Well, no. Carbohydrates are a larger part of the mix in high-intensity swimming. Most of swimming is warm-ups and training, and much of training is at a lower intensity where carbohydrates do not provide most of the fuel. Not to mention the rest of life. Two slides previous coaches were encouraged to tell swimmers to think of themselves as a “24/7 Athlete.” Over the course of any 24 hour period, where 2-4 hours are in the pool, athletes get about 70% of their energy from fat. Primary fuel source = fat.

At highest intensities, muscle glycogen (stored carbohydrate) supplies most of the energy. At more moderate workout intensities, fat (muscle triglyceride and plasma free-fatty acids) contribute the bulk of energy. As is obvious from this chart, in any 24 hour period where a swimmer trains for 2-4 hours, fats are the primary fuel source.

The next slide claims that carbohydrates should be “60% of calories.” Says who? ACSM 2016 offers no such dietary percentage. It would be pointless. I mean, people do a terrible job tracking how much they eat, so 60% of an unknown number is an unknown number. Also, the presenter ought to give some evidence that such a high carbohydrate fraction is a good idea. Here, for example, is a chart from one studying showing that as the carbohydrate (CHO) fraction of the diet was reduced, both male and female endurance athletes consumed more and performed better.

CHO is carbohydrate. ’67’ refers to athlete diets where 67% of energy came from carbohydrate. ’55’ refers to 55% CHO, ’42’ refers to 42%. CHO reductions were offset with increased fat consumption. Top endurance performances for women were found at 42% carbohydrate, whereas men performed best at either 55% or 42% CHO.

More on this slideshow in Part 2.

The Mantra Problem

Below is a list of words and phrases that nutritionists use with mantra-like frequency. Like a mantra, these phrases have lost any actual meaning, and are used to fill space (or possibly signal virtue), not convey information. They are a red flag that gibberish lies ahead.


whole grains

low-fat dairy

lean meats

healthy fats

naturally occurring sugars

USA Swimming gives some bad nutritional advice on dietary fat, Part 2

Big mistake #2: The author forgot the audience.

Screen Shot 2018-12-02 at 11.47.07 AMThis is nutritional advice for the athletes of USA Swimming. In 2016, there were 336,036 year-round swimmers in USA Swimming. More than 96% of these swimmers were 18 or younger (and 56% are female).

There is currently no evidence that endurance-trained athletes under the age of 18 suffer from cardiovascular disease brought on by consumption of dietary fats.

Young athletes do (rarely but tragically) suffer from, and die of, cardiovascular diseases. Hypertrophic cardiomyopathy is the most common of the (still very uncommon) genetic heart abnormalities that afflict young athletes. Here’s the thing though. Hypertrophic cardiomyopathy is a genetic condition. It is not caused by eating coconut oil.

You want to clear the confusion on fat for young swimmers? Start by telling them:

  • Don’t worry about it.
  • Right now, researchers disagree about the health value of various fats – saturated, monounsaturated, polyunsaturated.
  • Most things you’ll hear about dietary fats and health are wrong, so ignore it.
  • There is no evidence that any dietary fats pose a health risk to fit young athletes.
  • You may want to review current nutritional guidelines when you are in your 20s.

Parsing the different types of fats based on saturation, as the author does, and saying that some fats need to be avoided might (or might not) be useful for sedentary middle-aged office workers.

For the audience of young swimmers, this message on dietary fat is a needless distraction at best. And it potentially causes confusion, and fear, about food in general.

For most teen and preteen athletes, their primary nutritional challenge is to simply eat more food. They have limited time (and appetite) to consume the food needed to grow to their full potential and compete in the arena of their choosing. Their parents are unlikely to have the time to do independent nutritional research. These families need good, simple advice.

It is irresponsible to indulge your personal anxieties about the dangers of saturated fat when you are talking to teenage endurance athletes. You especially put at risk your largest and most vulnerable audience, those young female athletes who appear to be at greatest risk of undereating saturated fat.

More on that when we discuss the (serious and dangerous) female athlete triad.

The standard disclaimer: I am a parent of a serious teen swimmer. I am not a physician. I do not hold any certification in the field of nutrition. I am not a registered dietician. I read research publications and nutrition reports, but I do not do any independent research. Basically, I am lay-person, motivated by my concern for the well-being of my kid. For me to be able to tell that nutritional advice is bad, it has to be really bad.


USA Swimming gives some bad nutritional advice on dietary fat, Part 1

USA Swimming offers lots of odd, out-dated, and ill-informed nutritional advice to young swimmers. This series of posts are offered as a corrective.

Today we consider “Clearing the Confusion on Fat” written by Chris Rosenbloom Ph.D., RDN, CSSD. Let’s jump right in.

Big mistake #1: The author makes a significant factual error.

The author claims:

Saturated fats, like coconut oil, butter, and palm oil, raise risk of CVD.

Eh, no. The author defines CVD (cardiovascular disease) as “heart disease, blood vessel disease like high blood pressure, peripheral vascular diseases, and stroke”.

Even researchers who are wary of dietary saturated fat note there is no link to stroke. Here’s a typical quote:

…the available evidence suggests that SAFA [saturated fatty acid] reduction has little, if any, direct effect on stroke risk, but that the consumption of SAFA-rich dairy foods may be associated with a lower risk of ischemic stroke. 

You catch that last part? Dietary saturated fat may reduce the risk of stroke. Surprise! And if you control for body-mass, it looks like dietary saturated fat is not associated with high blood pressure either.

Yes, many public health officials express concern about a link between dietary saturated fat and increased risk of heart disease. But those links only pop-up among certain populations (generally middle-aged non-athletes) and even there the magnitude of the effect is slight.

For instance, a 2015 Cochrane meta-analysis did find a small benefit associated with swapping out some saturated fat and replacing it with polyunsaturated fats, but it was only the sicker, older study participants that received the slightest benefit, and only on one indicator – the frequency of heart disease.

That correlation would be significant except reducing saturated fat intake did not reduce the rate of DEATH from heart disease. How can that be? Well, a lot of times in dietary studies a ‘small effect’ and ‘no effect’ are kind of the same thing.

Others look at the same studies and see no benefit to reducing saturated fat intake. Their research suggests that dietary saturated fat is harmless.

Finally, for teenage female athletes, there’s reason to believe that a higher level of saturated fat intake is beneficial (the link is a study on the associations between fiber, vegetable protein, and poor bone density, but if you read through the other associations you see that the dietary element most associated with good bone density is saturated fat).

Perhaps the author of this USA Swimming article (Rosenbloom) has excellent reason to disagree with this body of research. If so, the author needs to say that. Or avoid the subject entirely.

Look for USA Swimming gives some bad nutritional advice on dietary fat, Part 2 coming soon.

The standard disclaimer: I am a parent of a serious teen swimmer. I am not a physician. I do not hold any certification in the field of nutrition. I am not a registered dietician. I read research publications and nutrition reports, but I do not do any independent research. Basically, I am lay-person, motivated by my concern for the well-being of my kid. For me to be able to tell that nutritional advice is bad, it has to be really bad.


ACSM 2016 – “Nutrition and Athletic Performance,” by the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine (2016)

Quite the document and worth reading. I don’t mean to suggest that consensus documents from big public health institutions are generally very useful for athletes, especially teenage athletes. They aren’t. This one is, though. It is focused on athletes. And it calmly deals with a number of superstitions often heard on the pool deck.


  • Crashing blood sugar: Conventional advice holds that athletes should seek out snacks with higher fiber and ‘natural’ sugars (derived from fruit). The rationale is that these nutrients will help prevent spikes and crashes in blood sugar. But among the most strongly supported findings presented on carbohydrates and training is the simple observation that these supposed blood sugar spikes and crashes do not affect athletic performance.
  • Sucrose. The best source of quick energy (based on the evidence reviewed here) is glucose + fructose. And common table sugar is glucose (50%) + fructose (50%). So don’t overthink it. (2) 
  • Protein: Consume some protein during recovery.
  • Beware ‘low-energy availability!’ The report rings the alarm bells. Teenage athletes can be eating normally, participating fully in their sport, performing academically, and acting like a normal teenager while running up a potentially dangerous deficit in energy intake. First to suffer are unseen metabolic processes like bone density maintenance. Don’t let this happen.
  • Dietary fat: ‘Fat is a necessary component of a healthy diet, providing energy, essential elements of cell membranes and facilitation of the absorption of fat-soluble vitamins.’
  • Saturated fat: The report notes (at arm’s length) that two government agencies recommend restricting saturated fat to 10% of total caloric intake. Those agencies cite, as the basis for that restriction, studies on dietary fat and heart disease. Those studies are controversial. (1) The ‘10%’ number is a mystery. It does not come from the studies. The highly influential Institutes of Medicine nutritional guidelines estimate that in most diets, saturated fat will be about 10% of total calories. But that’s an estimate, not a limit, and the IOM is very clear that 10% is not a restriction.
  • Very-low carbohydrate diets are probably not a great choice for swimmers.
(1) In just about every case, reducing saturated fat intake made no difference for otherwise healthy people. The one exception was odd. Older people with bad lipid panels appeared to get some small benefit by substituting polyunsaturated fat for saturated fat. And the benefit was dubious. They were (slightly) less likely to be diagnosed with heart disease. But no less likely to DIE from heart disease. Put another way, if your concern is whether you DIE from heart disease, then these studies provide no evidence that you should reduce your consumption of dietary saturated fat.
(2) Though not covered in this report, fructose (fruit sugar) metabolism is pretty cool. Unlike glucose, most cells in the human body cannot use fructose directly. So the body sends the fructose to the liver (mostly) where it is converted into mostly glucose, along with some lactate, and a little fat (triglyceride). All three components can be used by skeletal muscle for energy production. Fructose conversion is its own weird little pathway. And that’s a good thing. Because during exercise, when glucose utilization is maximally stimulated, you can increase overall muscle energy provision by adding fructose to the mix. Sounds great. But where can we find glucose and fructose conveniently packaged together? Basically, everywhere. Brown sugar, white sugar, cane sugar, beet sugar, high-fructose corn-syrup, barley malt, molasses, honey, agave syrup, etc are combinations of glucose and fructose.