The low down on carbs - Keep it simple, keep it starchy

This is a contentious topic, one I have had to go full circle on, twice.

My journey into all things food was really catapulted by my interest in CrossFit about 5 years ago. An inevitable companion to CrossFit is the Paleo diet (see here for a quick overview of the paleo diet) which for many reasons is a great thing and the reason I have arrived at where I am today, so this is NOT a slam on the paleo diet. However, a major problem with paleo is the concept of vilifying certain grains and carbohydrate products. This is an ill founded position, particularly if you are training and want to increase lean muscle tissue; a fundamental goal in almost everyone I work with both clinically and in conditioning.

The following is how Alan Aragon approaches carbohydrate ingestion and having checked out his support material, I am very confident in the recommendations and his reasoning. Over to Alan (Lean Muscle Diet P.23-27):1

"Carbohydrates do one thing, provide energy. If you look at the broad outlines of human metabolism, you'd assume they do it pretty well. Your brain uses 20 percent of your daily energy - 500 calories for a guy eating 2500 calories a day. All of it comes from a sugar called glucose. No matter what type of carbohydrate you eat - bananas, fettuccine, gummy frogs - it all turns to glucose during digestion. from there it is the preferred fuel for both mind and muscles.

In fact, glucose is so important to your survival that your body does not trust carbohydrates to provide it. Through a process called gluconeogensis, you can make glucose out of amino acids. It seems to occur even if you have plenty of carbs in your diet.

So, in the most literal sense, carbohydrates don't matter for short term survival. But they sure as hell matter in all practical ways. They are crucial to athletic performance, especially in endurance events but also, to a lesser extent in sports like soccer and basketball which require a mix of stamina and bursts of speed and power. 

The average American mans diet is about 48 percent carbs. Those who are classified as overweight and obese don't eat a higher percentage than those who are considered "normal" weight. Think about that for a moment. While the heaviest people clearly eat the most food, it doesn't follow that they eat the highest proportion of carbs. Nor does it follow that cutting carbs is the best weight strategy for everyone. Before we get there, lets clear up some definitional issues. 

The Meaningless Classifications that Launched a Thousand Stupid Arguments

You've heard carbohydrates described as "simple" or "complex". A simple carb has only one type of sugar. That sugar can be a monosaccharide, like fructose or glucose, or it can be a disaccharide, like sucrose, better known as table sugar, which combines glucose with fructose. Complex carbs are usually polysaccharides: long chains of sugar molecules. 

Typically, if someone uses the word "complex" in front of "carbohydrate", its to imply it is superior to a simple carb. Problem is, an apple is a simple carb, as are lots of healthy, nutritious foods. And white bread, long used as a worst-case example of food processing, is complex. 

A better word for complex carbs is starch. Starches are found in most of the foods we eat: cereal grains (wheat, corn, rice, oats), tubers (potatoes, sweet potatoes, yams) and beans. Even bananas start out with some starch, which turns to glucose and fructose as they ripen. From that list of foods, you can't make any blanket statements about the nutritious qualities of starches. You find them in both the most and least processed foods, from pastries to baked potatoes. 

Since we live in a carbophobic age, lots of people out there want to make these choices easy for you. Some diets, like Atkins, tell you to avoid almost all carbohydrates, no matter if they are simple or complex. Others, like paleo, make distinctions based on how long something has been a part of the human diet. Still others tell you that wheat is the problem. Shit will kill you, man!

Since we live in a carbophobic age, lots of people want to make these choices easy for you, including the Atkins and paleo diets

Meanwhile the longest lived people in the world eat diets based on starches, as described in the book Blue Zones, by Dan Buettner.2 These include whole grains (on Ikaria, a Greek Island; rice, beans and corn (Nicoya in Costa Rica); and Barley and fava beans (Sardinia, an Italian island).

"Because Insulin"

If your body were the US government, the hormone insulin would be the executive branch. You only think it runs the show because it gets the head-lines. That's why insulin gets blamed for every ounce of fat that ends up on your love handles, and gets none of the credit for the important work it does to build your muscles and keep you from overeating. 

We know that eating carbohydrates causes insulin to surge, and the more carbs you eat, the higher it goes (protein has a similar effect, but we don't often mention that, see figure 1 below). When insulin levels are high, your body can't release stored energy from your fat cells, which means you are temporarily more dependent on using glucose for energy. That is not a problem in the short term. As noted earlier, your brain, muscles and neurons run on glucose, and getting it directly form carbohydrates in your food is easier than making it from amino acids or taking it from the glycogen stored in your muscles and liver. 


Figure 1: In the above study the authors compared the effects of two different meals on insulin.* One meal comprised of 21g protein and 125g carbohydrate (Low protein / high carb - LP/HC). The other meal contained 75g protein and 75g carbohydrate (High protein low carb -HP/LC) and both meals totalled out at 675 calories. The image above left show the effects the two meals had on blood sugar levels whilst their effect on blood insulin can be seen on the right. Hopefully it is clear that while the blood glucose response was much higher in the high carb meal (left graph), the insulin response was not (right graph). The high protein meal induced a greater insulin response than did carbs contrary to popular carbohydrate-insulin-obesity theory, although he authors noted this did not reach significance3.**

*Image reproduced with kind permission from James Krieger of Weightology Weekly

If you're healthy, your body will quickly return to a normal state, with the glucose successfully cleared from the blood stream and your metabolism humming along on a mix of fuels that includes more fat than glucose. One way your body achieves that is with insulin. It acts as a powerful break on your appetite while shuttling the food you just ate into the appropriate places - muscles, liver, fat cells. 

Insulin gets a bad rap in fad diets because of that last thing: pushing excess nutrients -both fat and carbs - into fat cells. It misses the reward we get when it also shuttles protein into muscle cells with training

Insulin gets a bad rap in the fad diets because of that last thing: pushing excess nutrients-both fat and carbs-into fat cells (and it gets too little credit for pushing protein into muscle cells, which is the reward for all hard work in the gym). But even that is no big deal. Fat cells aren't prison cells. Energy goes in and out all the time. Its only when you are eating more food than your body can use that you have to worry. Thats not because of insulin-its because you ate too damned much (see figure 2 below).

Figure 2: After meals, fat is deposited with the help of insulin. However, between meals and during sleep, fat is lost. Fat balance will be zero over a 24 hour period if energy intake matches energy expenditure - in a nutshell: if we eat less, and move more.     *Image reproduced with kind permission from James Krieger of Weightology Weekly. 

Figure 2: After meals, fat is deposited with the help of insulin. However, between meals and during sleep, fat is lost. Fat balance will be zero over a 24 hour period if energy intake matches energy expenditure - in a nutshell: if we eat less, and move more.

*Image reproduced with kind permission from James Krieger of Weightology Weekly. 

For the more critical eyed reader, you are directed to James Krieger's fantastic 6 part series on the role of insulin; part 1, part 2, part 3, part 4, part 6 (part 5 is more of a defence against critics struggling with the cognitive dissonance of solid myth busting science!).

Clearly though, some of us handle our carbs better than others. Put another way, some of us are more sensitive to the effects of insulin than others. That means we need less of it to sweep glucose from our blood stream, and it works better as an appetite killer. A university of Colorado study, published in 2005, showed how insulin sensitivity can affect weight loss.4

Women in the study were assigned a diet that was either low-carb (20 percent carbs, 60 percent fat) or low-fat (60 percent carbs, 20 percent fat). Both diets had 20 percent protein. The women classified as insulin-sensitive lost twice as much weight on the low-fat diet; those classified as insulin-resistant lost more weight on the low-carb diet. 

There is only so much you can read into any single study (especially when you are a guy and the subjects were women), but in this case it matches what Alan and other weight loss specialists see pretty much every day. If you have a lot of weight to lose, and especially if you are a couple of years behind on your workouts, you probably have some degree of insulin resistance. High-carb meals will create more problems for you than they will for someone who's leaner and has a higher fines level.

Most people following a "Lean Muscle Plan" would get about 40 percent of a 2500 calorie diet from carbohydrates. You will also get about 30 percent from protein which leaves 30 per cent for fat. In other words, the classic 40:30:30 Zone diet". 

If it hasn't become clear by now, carbohydrates are NOT your enemy, and the usual frustrating answer "it depends" has hopefully been outlined in this page. 

Contact Luke R. Davies for programming, expect plenty of carbohydrates. Keep things simple, keep them starchy. :)

Luke R. Davies :)


1. Aragon, A and Schuler, L. (2014). The Lean Muscle Diet, Rodale Inc. New York USA, P.23-27.

2. Buettner, D. (2012). The blue Zones 2nd Edition: 9 Lessons for Living Longer From the People Who Have Lived the Longest, National Geographic 2nd Edition Edition, USA.

3. Boelsma, E., Brink, E. J. Stafleu, A. and Hendriks, H. F. (2010). Measures of Postprandial Wellness after Single Intake of Two Protein-carbohydrate meals, Appetite, 54(3), P.456-64.

4. Cornier, M. A., Donahoo, W. T., Pereira, R., Gurevich, I., Westergren, R., Enerback, S., Eckel, P. J., Goalstone, M. L., Eckel, R. H. and Draznin, B. (2005). Insulin Sensitivity Determines the Effectiveness of Dietary Macronutrient Composition on Weight Loss in Obese Women, Obesity Research, 13(4), P.703-9.

5.Krieger, J. Weightology Weekly accessible at: