High Carb vs High Fat

By Jordan Feigenbaum MS, CSCS, HFS, USAW Club Coach

In recent times there has been a rather large surge of people who are afraid to eat carbohydrates. This is in stark contrast to the low-fat era of the 80’s and 90’s where people were afraid to eat a single gram of fat. Ultimately, there seems to be a large stand-off brewing when it comes to whether or not carbohydrates or fats should be the main energy substrate between these two camps, which is surprising to me given both the anecdotal and experimental evidence for both camps. I’ll start off this whole article by establishing my position on this very topic, either way works but you’re specific physiology, goals, and training style will likely work better with one or the other.

To begin, I need to define a few terms for the sake of clarity. A diet is the daily or weekly levels for protein, carbohydrates, and fat. A diet that is low in carbohydrates is traditionally high(er) in fats and conversely, a diet that is low in fat is high(er) in carbohydrates. While it is possible to go both low fat and low carbohydrate, this is only achievable with the use of either protein powders or other commercially available products that allow have stripped the fat out of these condensed protein sources. I suppose someone could live on egg whites, boneless/skinless chicken breast, and tuna to get their protein in without much in the way of fat, however I will refer to these low carb AND low fat diets as modified protein-sparing diets. They are good for extremely rapid body fat loss, but not so good for ultimate aesthetic achievement or performance. That being said, when someone restricts carbohydrates (i.e. low carb), they must eat something else for calories, which usually come from either fattier protein sources, oils, and condensed fat sources. I will hereby define a low carbohydrate diet as a nutritional protocol that has less than 20% of total calories coming from carbohydrate sources. On the other hand, when someone restricts fat intake, lean protein sources must be used and the calories in the diet are obtained from dense carbohydrate sources like potatoes, fruits, roots, oats, rice, wheat products (if gluten is tolerated), and other similar carbohydrate-rich foods. I’ll hereby define a “low fat” dietary approach as any diet that has less than 20% of total calories coming from fat.

Determining which approach is better for you and your goals could lead us down a series of very extensive thought experiments, but we’d eventually end up in a place where you’d just have to experiment on your own for any real, meaningful answers. The God’s honest truth is that either fat or carbohydrates can be oxidized (burnt) by mitochondria in human tissues to create energy. Human’s have the machinery on deck to use either fuel, although when a mixed diet is consumed (i.e. one with significant amounts of carbs and fats) the cellular machinery used to oxidize sugar (carbohydrates) is much more robust than the machinery for fats. When intake of carbohydrates is restricted for a significant period of time, the cellular machinery for fat oxidation is upregulated (increased) so that the body becomes more efficient and adept to use fat as its main fuel. This process can take anywhere from a couple of days to a few weeks for some people. This also explains the lethargy, weakness, and transient decreased recovery capacity of those shifting to a lower carbohydrate diet. Another variable that we’re not taking into consideration here is overall caloric intake. All of the previous discussion is under the assumption of isocaloric conditions. People who decrease carbohydrate intake tend to subconsciously take in less calories per day, for many reasons relating to palatability of food, reward mechanisms, satiety signaling, etc. At any rate, being that we can use either substrate, fat or carbohydrate, for fuel, the question of what kind of setup is better really depends on where you’re at currently with compliance to dietary advice, training intensity/volume, and your overall goals.

High-volume, high-intensity, or training programs that have significant amounts of conditioning built into them seem to require a larger percentage of calories coming from carbohydrates as compared to low-volume or low-intensity programs that are devoid of conditioning. The idea behind all this is kind of an earn your carbs thing. While it is certainly possible to restrict calories enough, and make no mistake about it- this is the biggest key to weight loss, and still keep carbohydrates as a large component of the diet, lower carbohydrate versions seem to work better for sedentary/lightly active populations. This is probably due to increased satiety from low-carb diets, increased protein intake to maintain the lean body mass/increase satiety, and the greater bio-availability of micronutrients in low carb diets. Many carbohydrate dense foods have their vitamins and minerals rendered less availble by certain anti-nutrients -phytate, glycoalkaloids, and other lectins- effect on digestion and absorption.  At any rate, you must decide what category you lean more towards?

It’s possible to get away with lower amounts of carbohydrates and/or calories when the volume is low, as determined by reps, sets, number of exercises, and frequency. Additionally, if strength, performance, and conditioning are not the ultimate goals, lower carbohydrate diets offer plenty of potential benefits as previously mentioned, when weight loss is the number one goal. Perhaps the best thing about low carbohydrate diets is that most of the time the compliance is high, while at the same time being easier for the individual to comply with. So not only is it fairly easy to do, it’s pretty easy to do consistently. What I mean by “easier to comply”, is that I can tell someone to avoid starchy carbohydrates like bread, rice, pasta, potatoes, oats, products with flour, etc, and that is fairly well understood by most lay people. Additionally, I haven’t had to tell them how many calories to take in, grams of protein, etc. This very simple advice typically results in a spontaneous decrease in caloric intake, a shift to more unprocessed foods, and best of all- RESULTS. Positive changes in body weight, fat mass, blood work, etc. are all seen in low carbohydrate diets, and when all this can be gleaned from the single line of “avoid starchy carbohydrates”, then we’ve got a pretty powerful AND well understood tool for weight loss. Most people probably “mess up” the low-carb diet by either not actually eliminating carbohydrate dense food, like thinking pretzels are not made of flour but instead, they are magical food products made of only air, or by eating too much fat from nuts or nut butters.

It is my opinion, that a true low-carb diet, < 20% of total calories from carbohydrates, should only be reserved for people with a lot of weight to loose, those who are inactive, those who won’t count calories, and those with pathologies that respond to ketogenic diets. Certainly in the prep for physique-sport athletes there will come a time when carbohydrates will have to be reduced, but this is only a short term solution for a looming show or meet.

The benefits to keeping a significant amount of carbohydrates in the diet are numerous. For brevity’s sake the most important ones are that carbohydrates spare protein (important during caloric deficits), replenish glycogen stores, provide fuel for high-volume and high-intensity training, etc. The downsides for keeping carbohydrates in the diet is they are easy to overdo, as a “serving size” can easily be doubled or tripled unless you’re actually weigh and measure your food. The old saying “carbs beget carbs” is also true for some people and inclusion of a moderate amount of carbohydrates without adherence to a strict nutritional program can lead to straight up binges on carbohydrate-dense foods, which may ruin an entire week’s worth of diligence on a diet. Pathology-wise, certain disease states respond better to a low carbohydrate or ketogenic protocol, namely certain epithelial cell-derived cancers, diabetes, autism spectrum disorders (ASD), diseases of the kidney, and certain autoimmune conditions.

At any rate, we’re talking about high level performance and aesthetics in this article. In my opinion, many people forgo carbohydrates because they have an irrational belief that they are super sensitive to glucose or insulin. The idea that isocaloric preparations of a low carbohydrate diet will outperform a higher carbohydrate date (both made up of quality foods) has not been demonstrated in strength/power or physique sports. The top of the top continue to give us the same anecdote, eating quality foods in specific quantities that are relatively high in protein, moderate to high in carbohydrate (sometimes this undulates via carbohydrate cycling), and low in fat. Bodybuilders, who are THE BEST IN THE WORLD at getting really lean and retaining muscle, continue to live off egg whites, rice, chicken, fish, lean beef, potatoes, veggies, etc. Notice however, that we’re not talking about ultimate health in this situation, we’re talking about ultimate performance. You’ve got to give a little to get a little.

As Dave Tate says “Health stops when the competition starts.” No one would (or should) argue that getting down to 4-5% bodyfat, shedding water, and carbing up is a prime example of health. Similarly, no one would say that aiming for an elite powerlifting total confers a high level of health and wellness to its pursuant. If health is what you’re after with performance being a secondary consideration your diet might look like this:

Breakfast: 4 scrambled organic free range omega 3 eggs over low heat in coconut oil. mixed organic berries in a cup of Kefir on the side. Black coffee with heavy whipping cream.

Lunch: wild caught salmon, sweet potatoes, side of broccoli


Post Workout: Free range organic chicken and white rice

Dinner: lean grass-fed steak w/ grass fed butter, asparagus slow cooked in olive oil

Notice that carbohydrates fall only around workout times. I would basically instruct someone not interested in counting calories to stick to a “fist-sized” portion of organic/free range/grass-fed protein and a variety of vegetables and healthy fats (coconut oil, walnut oil, macadamian nut oil, olive oil, ghee, kerrygold butter, etc) each meal outside of this workout window. In the meals surrounding the workout time add in a fist sized portion of yams, sweet potatoes, rice, or similar for a whack of carbs. This would be pretty optimal for someone who won’t count, weigh, measure, or track their intake, but yet wants to remain lean with decent performance.

Outside of that, I stick by my original thoughts on the high-carb vs low-carb argument. For some, they will need to gradually reduce carbohydrates to a very low point to get as lean as they want. For others, they won’t need to do this because of their genetics, training history, metabolism, etc. It’s just too dependent on a variety of factors to say definitively what works for every single damn person.

My suggestion if you want to recompose your body into a leaner, more capable version of yourself is to start around 1.5g of protein/lb of bodweight, 1g/lb of carbohydrates/lb of bodyweight, and 0.5g/lb of bodyweight of fat. Take pictures each week and weigh yourself too. If the mirror says your getting leaner then that’s it, keep at it. If the mirror isn’t agreeing with you AND the scale isn’t moving then it’s time to adjust your energy substrates, carbs and fat, down a bit to see progress. Honestly though, most people will see immediate improvements from just tracking their macros and calories and adhering to an intelligent nutritional protocol. Most people eat ad libitum with a large variance in total calories and macros everyday. Complying with a strict-er diet plan usually causes improvements in body composition off the bat. Only later on when the goals become more focused will there be a need to titrate energy intake up or down.

Overall, I’m not a huge fan of sustained low-carb interventions, but not because they don’t work- they do! Rather, I find that the need for chronically being low carb in healthy populations is almost non-existent except in those who are not complying with the diet recommendations anyway. Low or low-er carb interventions should be reserved for specific periods of fat loss, not for performance goals. So, what category do you fall into?

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About thefitcoach

An aspiring physician, I've been involved in the strength and conditioning world for over 5 years now in a professional sense. I started this blog with some like-minded individuals to share our thoughts on training, nutrition, lifestyle, medicine, health, and everything in between.

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