As an athlete and coach, I’m clearly interested in all things training related. What workouts should I do? When should I do these workouts? How many rest days should I take? All of these are key questions that most every athlete will consider when looking to work towards some goal.
What should I eat, when, and how much? These questions may well be just as important as those regarding how to train. To address the topic briefly, here are some basic guidelines that I think are healthy and should help you train and perform well, which are guidelines that I generally try to follow with my diet. As an aside, if you looked around at other dietary guidelines and asked me to compare my approach to others’ or to say what’s similar, I’d say that my thoughts on diet are probably most closely aligned with Tim Ferris’ “slow-carb diet” and Cordain/Friel’s “Paleo Diet for Athletes.” I do include fruits in moderation, which Ferriss does not. I also include legumes, which the Paleo diet does not include. I’ll include oats and other grains some of the time, but neither diet really advocates for that.
Eat vegetables and legumes in abundance. You can never add unhealthy or performance hindering body weight from eating too many vegetables. You’ll get the highest ratio of nutrition to calories that you can. With legumes (beans and lentils) you can add fiber, protein, minerals, and slowly digested carbohydrate to your diet. Eating a ton of this stuff will likely keep you healthy, lean, help repair muscles, feed healthy gut flora, help give you energy for workouts, and likely reduce your risk of most every disease out there. It’s probably impossible to eat too many vegetables or legumes, so go ahead and include them however you can enjoy them. The only caution would be about how they’re prepared, so just be careful to keep extra ingredients limited (e.g. oil or butter with salad or vegetables, cheese with beans, etc.). Potatoes are considered a starch here for our purposes, not a vegetable, though it clearly also falls into that category.
Eat fruits and nuts in moderation. Fruits and nuts are both great sources of vitamins, minerals, fiber, and energy (in the form of carbohydrate and fat, respectively). Fruits also have the added bonus of providing a lot of water, helping make them good recovery foods (carbohydrate and water, both good for recovery). Nuts are good sources of protein, minerals, and arguably healthy fats. The challenge for each of these is the high fructose content of the fruit, which in general would be a bad thing, but when it’s packaged in its natural casing (i.e. whole fruit), fructose is probably fine for you in moderation. Likewise, nuts are good for you, but high in calories, so you just don’t want to consume too many of them. With that in mind, I’d say it’s probably fine to have both daily, but just keep it moderate.
Animal proteins are fine in moderation. Skip it if you’re vegan or vegetarian, and you’ll be fine too. Meat, eggs, and/or dairy can be a great source of protein, iron, some vitamins, and fat that can be used as fuel. There’s definitely some question about whether animal protein is ultimately all that good for athletic performance. Really it’s not at all necessary, but animal products may be helpful because they are a great source of protein that’s relatively easily assimilated, and have basically just the right stuff for adapting to hard training. The question about meat and dairy is more of a public health question regarding how much meat is safe to eat, what kind of meat is safe to eat, and whether dairy is safe to eat. Some people argue strongly against hormone and antibiotic fed meats, so in an ideal world, it’s probably good to avoid if you can. Dairy is strange because of the high insulin production that follows its consumption. That alone makes me question whether or when you might want it. Also, some people argue that high intake of dairy protein encourages the growth of cancer cells. I’ll admit that I really like yogurt, and eat it regularly, but otherwise, generally avoid milk products altogether, for the reasons above. Fish may have mercury and maybe other things you wouldn’t want to consume, but some fish has healthy fats, and they all have great protein, so it’s again debatable if or how much is going to be okay or good to eat. Lastly, there’s the fact that vegetarians tend to weigh less. Ultimately, I’ve gone back and forth over time about whether there seems to be sufficient justification to eat animal food products and about how much may be safe to eat, but where I stand now is that it’s probably fine in moderation, especially if you limit or avoid dairy and choose natural meats (grass-fed, free-range and non-farmed fish).
Include unrefined starches in proportion to high-intensity training or racing. The more you ride, lift weights, run, or otherwise workout, the more you’re going to need calories to fuel your activity, and the more intensely you do those things, the more carbohydrate you’ll use up. At lower intensities, you burn mostly fat, so replacing used up glycogen stores is much less crucial. If you eat a lot of carbohydrate, whether it’s sugars or starches, refined or not, it’s going to encourage your body to release insulin into your bloodstream and store glycogen and fat, which is fine at the right times, but not good if it’s a chronic condition in your body all of the time, because it will limit fat-burning and encourage undesirable and potentially unhealthy fat storage. Anyway, all that to say, consume extra carbohydrate in proportion to the high-intensity work that you do in your training, but limit it when you’re not doing as much. I think that potatoes are fine, but they’re pretty quickly digested and absorbed, so I’ll keep them reserved for after hard workouts or during stage races. Sweet potatoes and yams are great, because they have a some extra nutrients in them compared to white potatoes, but more importantly, they’re much more slowly digested and absorbed, so they cause less of a swing in your blood sugar and insulin levels. Likewise, I’m a big fan of oats, because they’re slowly digested, have more fiber and protein compared to some grains, and are gluten free (which some people like). I’m not a big fan of bread, pasta, rice, or related flour-based products. They are refined and shoot glucose into your bloodstream way more quickly. Personally, I avoid refined, flour-based products and rice almost all of the time, but again, will use them sometimes in hard training or during stage races.
Research on training versus diet: Everyone wants to get stronger, faster, better, etc. so everyone can justify doing studies on what kind of performance effects strength training, endurance training, interval training, etc will have on your performance, whether it’s power, endurance, speed over distance, etc. Somehow it seems that research related to diet is a little more one-sided, because most research on diet seems to be focused on public health and whether too many hamburgers will kill you or too many donuts will give you diabetes. With respect to performance, a lot of research is done with athletes to see how they perform if they drink nothing, drink water, or drink a sports drink. Some research is done to see if caffeine in your sports drink helps you out, or even if swishing-and-spitting a sports drink or caffeine drink helps you perform better (it does on both counts). It seems like most of this research is done to see acutely if performance is enhanced that day with that protocol, but I whenever I come across interesting studies on nutrition and sports, it’s usually not done on how long-term diet changes help or hinder performance.
So, all that being said, I think that there could be more real research done to answer the questions of what diet is best for performance in the long run, and whether that diet will be constant, or like your training, will vary significantly. I would argue that the latter is likely to be the case, that just as your training changes from day to day, week to week, and throughout the season, that if you change your diet along with your training, that you’ll likely be able to be healthier and perform better in the long run.
Does drinking a sports drink help you perform today? Yes; research clearly supports this idea. Does training with a sports drink every day help your VO2 or threshold power? Does it help your endurance? Does it hinder your endurance by hindering your body’s reliance on fat as a fuel source? Does it make sense to do endurance training with less carbohydrate and more intense threshold, aerobic capacity, and anaerobic capacity training with more carbohydrate? These questions are more interesting, but are harder to study, and likely will make a notable difference in the long run. Maybe it’s worth sacrificing a few watts on Saturday’s long ride by having less carbohydrate going into it, so that your body will have better endurance and perform better in the long run. Or maybe it’s not worth doing that, because you’ll still burn just as much fat, but have a better high-end aerobic workout on that ride. Maybe it will help you 3 months down the line to modify your diet like that, or maybe it won’t. I imagine that it probably would, the challenge is in the details and how to exactly implement that kind of change.