We get asked a lot from new members to the Science Lab which carbohydrate sources are best. Here is a good guide. Click here to find out how to join over 600 other athletes.
In recent years, while the rest of the world continued to live in fear of fat, the fitness community totally embraced it. Carbohydrates became the target of our frustrations; we blamed them for making us fat, compromising our immune function, keeping us inflamed, and generally ruining our lives. We’ve learned our lesson now and carbs have had their reputation restored. It’s really about time, considering the role that carbohydrates play in the performance of nearly every sport, especially weightlifting. Still, there are some things we need to discuss as far as what’s optimal.
Why Fruits Aren’t Optimal
Without a doubt, one of the hardest things to tell someone that’s seeking improved performance and body composition is that fruit should not make up the bulk of the carbohydrates in your diet. The reason is two-fold: first of all, as the nomenclature implies, most fruits are chock-full of fructose, as well as sucrose (which is just a compound of glucose bonded to fructose). As far as performance goes, these two leave a lot to be desired. Like glucose, after fructose has been cleaved into its separate parts, it’s instantly absorbed into the bloodstream during digestion and merrily sent on its way to the liver. However, while glucose sort of passes through and heads out to be utilized by other tissues by way of glycolysis, fructose metabolizes through its own unique pathway (fructolysis). It kind of hangs around and turns into pyruvate, then into glucose which is used to replenish liver glycogen storage. These stores are accessed to create glucose for other tissues during times of low blood sugar and stress, when plasma concentrations of glucocorticoids (like cortisol) are high. As far as performance goes, it’s nowhere near as efficient as simply storing glucose as readily-available glycogen within skeletal muscle.
The second issue here is that once liver glycogen is full, the rest of the fructose you ingest is promptly metabolized into triglycerides; consuming more than 50-75g a day (200-300 calories) is a surefire way to store body fat. This is especially true for women, who typically express a lower capacity to oxidize carbohydrate during intense exercise than men (although they do burn more fat). Now, that doesn’t mean that fruit is out the window. If you train hard 5-6x a week, your liver will hardly have an opportunity to fully replenish glycogen stores, and as valuable source of vitamins, minerals and fiber, fruits have definitely got their place in a balanced approach to nutrition. Furthermore, you’d have to eat a lot of fruit every day to reach that kind of fructose intake, and most fruits do provide glucose as well. To that end, you’d also have to eat a lot (and I mean a lot) of fruit to satisfy your carbohydrate/calorie requirements after training; it’s just not optimal (or in some cases, feasible) to rely upon fruit as an energy source. Thankfully, there are other natural sources of carbohydrate available that are positively brimming with glucose as well as important micronutrients.
Starches are an Athlete’s Best Friend
Starch is a glucose polymer found in most plants that is chemically similar to our endogenous glycogen; it’s literally just a long chain of glucose molecules bonded together. Although humans have a tough time digesting the stuff raw, cooking breaks it down into pure glucose ready for utilization as a substrate to produce cellular energy throughout your body. Of course, whatever you don’t use can be stored, preferably in your biceps, quadriceps or abdominals. While some of the most widely-consumed sources of starch (and thus glucose) are grains, like corn, wheat and rye, plenty of Paleo-friendly alternatives exist if that’s your thing. At the forefront, we have good ol’ fashioned tubers, like potatoes and carrots, as well as rice (preferably white because the fiber in brown rice actually impairs glucose loading a bit), but let us not forget chestnuts and acorns that are rich in starchy energy. Squash, peppers, zucchini and cauliflower round everything out and give you a wide palette of flavors to choose from.
Now, it is completely up to you whether you munch on sweet potatoes instead of white potatoes, or white rice over brown rice. It’s worth considering however that the fiber content of potato skin, as well as the germ of brown rice, can slow digestion. It’s not that big of a big deal, but it’s potentially disadvantageous in situations where we need to shoot for quick glucose uptake (like after training). The most important take-away here is that you need dietary glucose to effectively replenish muscle glycogen. If you’re really looking to optimize your carbohydrate strategy, you can take things a step further and get into supplementation through a few different means.
Carbohydrate Supplementation and Liquid Nutrition
Whole, natural foods should absolutely comprise the foundation of your nutrition. I won’t argue against that, but I do think that there are a few unique situations where integrating supplements into your plan can really bring your performance to the next level. The most important time to consider what’s been coined as a “recovery drink” is immediately after your training. This can make a dramatic impact on your energy levels and recovery if it’s formulated properly, and you have a plethora of options available should you go this route. On one end of the spectrum, you could throw a potato into a food processor along with some coconut milk, and wind up with one of the most interesting-yet-effective post-workout drinks known to man. Alternatively, a mottled banana with some dark chocolate in a coconut milk base may be slightly more appetizing (and socially acceptable!). Add teaspoon of sea salt to either of these concoctions and you’ve got the perfect storm in terms of quick gastric emptying and nutrient absorption at the small intestine. If pureed foods aren’t quite your style, you can go the more traditional route and purchase a commercially available supplement.
At this avenue, your best bet is to go with modified starches like maltodextrin, dextrose and waxy maize; not only are they typically very affordable (especially if you buy in bulk), but they’ll blend right in with your favorite protein powder and provide you with exactly what you need to begin restoring glycogen within your muscles as soon as possible. 50-100g of maltodextrin or waxy maize will do the job but you can experiment with more or less based upon training intensity, duration, and the amount of muscle mass you carry around. As far as taste is concerned, dextrose is very sweet, whereas waxy maize and maltodextrin are generally bland and flavorless. This is worth considering, especially if you’d like to use a supplement as a means to beef up the carb content of an existing protein shake that you’re already incorporating post-workout. You probably won’t want to add any dextrose under these circumstances, but if you’re starting completely from scratch, a little bit can go a long way towards making the maltodextrin/waxy maize palatable. In addition, a bit of sodium to your post-workout nutrition can increase the rate of absorption of whatever other nutrients you’re ingesting, so throwing dextrose into the mix may be even more important (unless you grew up drinking salt water.)
Hopefully this information will help you make more optimal decisions in regards to where you get your carbs from. It really doesn’t make sense to exclude any one source, but the majority of your carbohydrates should come from starches and vegetables like potatoes, squash and rice. This will keep your muscles full and give you the energy you need to perform. Fruit should be approached as a means to supplement your micronutrients and round out your carbohydrate intake. To top it all off and make the most of your training, you should also consider implementing a liquid nutrition strategy post-workout.
- For a time, carbohydrates have been demonized, but they’re a great source of energy and an integral part of any nutrition plan that’s aimed at keeping performance at peak (or improving it).
- Fruits are not necessarily the best choice for fueling your muscles because they provide as much fructose as they do glucose. Fructose can only be stored in the liver as glycogen or as triglyceride in fat tissue. Your muscles need glucose to refill their energy stores.
- Still, fruits are packed with vitamins and minerals and are absolutely a part of a great nutrition plan. Try to keep your fructose intake below 75g every day; it isn’t hard to do at all if you don’t drink juices/sodas/sweetened teas etc.
- Starches are your best friend. Paleo-friendly alternatives include rice, potatoes, ripe bananas and oats. Make sure that you eat plenty of these in the evening to replenish muscle glycogen.
- Liquid nutrition in the form of pureed foods can be consumed before and during training; this can help you maintain performance during long training sessions or events.
- Supplementing with a carb powder like maltodextrin during or after training can be a great way to maximize recovery. If you drink a protein shake post-workout, adding maltodextrin is a great option. Also, throwing a little salt to the mix will help keep you hydrated.