Muscle Growth On A Low-Carbohydrate Diet"I want to try building muscle on a low-carbohydrate diet," a reader told me the other day. "I've just seen a study showing that it's the best way to lose fat and gain muscle. What do you think about it?" It would be great if there was one single diet that worked best for muscle growth, fat loss, athletic performance, optimal health or whatever else you can think of. Unfortunately, in my opinion at least, no such diet exists. If your goal is to gain the maximum amount of muscle in the shortest amount of time, the diet you follow will be very different to one designed for fat loss. I'll explain why in a moment. First, I want to address a few of the issues with the study supposedly showing that a low-carbohydrate diet is the best way to lose fat and gain muscle. Publishing their findings in the journal Metabolism, a group of researchers from the University of Connecticut tracked changes in body composition in a group of healthy, normal-weight men [1]. Of the 20 men taking part in the study, 12 switched from their normal diet to a low-carbohydrate ketogenic diet for six weeks. The other eight men continued with their normal diets. Foods eaten on the low-carbohydrate diet included beef (steak and hamburgers), cheese, eggs, peanut butter, various nuts and seeds, vegetables and protein powder (Super Whey Fuel and Fuel Plex Lite). Subjects were also told to avoid fruits and fruit juices, dairy products (with the exception of hard cheese and heavy cream), breads, cereals, rice, beans, and sweets. The men kept a food diary each day of the study (seven days during baseline and 42 days during the low-carbohydrate diet) and the control group kept seven-day records during weeks one and six. Here's what daily nutrient intake looked like in both groups during the final week of the study. Control group
Low-carbohydrate group
And the result? Total fat loss at the end of the six-week study was just over seven pounds in the low-carbohydrate group. The group following their normal diet lost no weight. The men following the low-carbohydrate diet gained just over two pounds of muscle. The control group, on the other hand, gained just under one pound. However, while the low-carbohydrate group gained twice as much muscle as the normal group (2 pounds vs. 1 pound), this doesn't necessarily mean that such a diet is the best way to pack on size. For one, although the subjects were told to record what they ate, there's no way of knowing how accurate these records were. Self reporting is a notoriously inaccurate way to estimate calorie intake. In some studies, people have been shown to underestimate their calorie intake by up to 50% [4]. In other words, someone who says they are eating 1500 calories per day may really be eating 3000 calories. If we're to believe the food records, subjects on the low-carbohydrate diet also ate a lot more protein than those in the control group (176 grams vs. 80 grams). So we can't say for sure whether it was the low carbohydrate content of the diet or the fact that it contained twice as much protein that had the biggest impact on muscle growth. You can read more about the optimal amount of protein required for gaining muscle in The New Rules On Protein And Muscle Growth. What's more, the low-carbohydrate diet was designed to promote weight loss, rather than weight gain. Muscle growth is usually a lot faster with a diet providing more calories and more carbohydrate than both of the diets tested in this trial. Taking six weeks to gain two pounds of muscle is nothing to write home about, especially when you compare it to the 5-6 pound muscular gain seen with higher carbohydrate intakes over the same period [2, 3]. Even the lead author of the study, Jeff Volek, PhD, RD, CSCS, believes that more carbohydrate is needed if you're trying to build muscle. Volek, a former Indiana state champion in powerlifting, is the co-author of numerous articles in scientific journals, with a number of book chapters, research presentations and abstracts wedged under his lifting belt. "If you are trying to gain weight," writes Volek in the November 2001 issue of Muscular Development magazine, "my experience is that it is very difficult to prevent weight loss, let alone gain weight, on a strict ketogenic diet." Volek also gave an interesting interview to Muscle & Fitness magazine, a relevant extract of which I've included below. Although I'm not recommending Muscle & Fitness as a reliable source of training and nutrition information, they do run the (very) occasional article that's worth reading. Here's what Volek has to say on the subject of carbohydrate and muscle growth... Q. Isn't a bodybuilder doing high-volume training going to run out of fuel if his glycogen stores aren't at least partially full, from carb consumption? A. When you start doing higher repetitions like bodybuilders do, at least during some phases of their training, I do think there's probably going to be some compromise in your ability to do those sets. You're going to start to build up lactate, you need to be able to deal with the acidosis, and the [ketogenic] diet doesn't really help that, and in fact may hinder that a little bit. But I certainly think it may have some application for ripping off some fat during certain phases of your training if you're a bodybuilder. I'm a powerlifter, so my workouts are low-repetition, high-intensity, and I find I can do pretty well on a low-carb diet, because the primary energy system you're using for those types of workouts is almost all phosphagen [immediate energy that is stored in the muscle] metabolism. I also have to compete in a weight class, and I've found it pretty effective for keeping my weight down and still keeping my lean body mass. Glycogen levels aren't totally depleted on the diet; they're about 50% of what you would have on a normal diet, and that's plenty to do the types of workouts a powerlifter does. So I think it can work for powerlifters and people in weight-class sports, but for bodybuilders or anybody who's involved with exercise that's more dependent on glycogen metabolism, you're either going to have to do a moderate version of it or cycle on and off it, so you can bump up your glycogen levels during certain phases of training. Q. Give me your best nutrition pointer for someone in a hypertrophy training cycle. A. If you're in an anabolic phase, you've got to be eating enough, number one. For natural bodybuilders you're really going to compromise your ability to put on muscle if you're on a low-calorie diet and trying to burn fat at the same time. That's something that you've just got to come to grips with mentally, and decide, Okay I'm in this phase of my training, I've got to, focus on putting lean body mass on, and I'll be okay mentally if I put on a little, fat during this time period. You've really got to understand that you can't optimize both of those at the same time. This brings me to the subject of exercise. In an ideal world, both groups would have followed the same exercise program. But that doesn't appear to have happened in this particular study. The only information about the type of exercise routine used in the research was this: "Subjects were moderately active performing a variety of different aerobic and weight-training routines, but none were competitive athletes. In the carbohydrate-restricted diet group, 1 subject was sedentary, 5 performed regular exercise (2 to 4 times per week for 20 to 60 minutes) and 6 performed a combination of aerobic exercise (3 to 5 times per week for 15 to 90 minutes) and resistance exercise (2 to 6 times per week for 45 to 120 minutes). Subjects were required to maintain their current level of physical activity during the study." So, what this means is that a) all of the subjects in the low-carbohydrate group were following a different exercise program and b) we have no idea what sort of exercise the control group was doing. In other words, any differences in muscle growth between the two groups could have been due to a better training program rather than diet alone. My own view on the subject is that low-carbohydrate ketogenic diets are not the best way to gain muscle, although they do tend to work well if you're trying to shed fat. If you want to do a bit of both (i.e. adding muscle to your chest, shoulders and arms while shifting the fat from your belly), take a look at How To Get Bigger Muscles And Six-Pack Abs, which explains some of the difficulties you might encounter as well as proposing a few practical solutions.
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