Cutting Diets & Carbohydrates: Do You Need To Go “Low-carb?”

It is considered an absolute truth that to get shredded you must cut or cycle carbohydrate intake. Learn why carbs might just be helpful during periods of fat loss.

One thing that seems to pervade the health and fitness industry is the supposition that carbohydrates must always be highly restricted when it dieting for fat loss. I have an inkling that this attitude arises from the ol’ “can’t have your cake and eat it too” idiom but the reality is that, you can in fact shred off that unwanted fat while keeping a good amount of carbohydrates in your diet, it just takes a little experimentation and tweaking.

Of course, this isn’t to say that you don’t need to be conscious of your carbohydrate intake, but more so that carbohydrates aren’t necessarily the enemy when it comes to fat loss (and are actually quite the opposite in reality). So in this article we will take a look at the benefits of cutting diets that maintains a balanced proportion of all macronutrients (proteins, carbohydrates and fats) and provide advice on how to tweak it if your fat loss efforts stall.

Carbohydrates reconsidered

One thing that low-carb supporters seem to fall back on when defending their stance of restricting, if not practically eliminating, intake of carbohydrates is that carbs are not technically an essential nutrient for humans; that is, to say, that we can theoretically (and biochemically) subsist without them. While that may be true, it doesn’t necessarily mean it’s optimal.

I think one of the more common misconstrued messages that seems to float around is that carbohydrates cause insulin to be released and insulin is a storage molecule so it will prevent fat loss. This is a rather close-minded way of looking that the physiology of the human body and doesn’t take into account many other factors or the bigger picture. This article will touch on the necessity of insulin in the next section.

Another thing people will say (generally the Paleo dieting advocates) is that the human species isn’t evolved to run on carbohydrates, specifically grains and refined carbs. I don’t intend on making this article yet another longwinded debate over the theory of how humans have evolved to subsist nutritionally in comparison to our Paleolithic counterparts, but I will say that the idea that carbohydrates are somehow detrimental to our health and wellbeing just doesn’t hold up from a physiological standpoint when you consider how many bodybuilders actually eat a substantial amount of grains and refined carbs yet achieve peak conditioning.

And yes, many of those same bodybuilders have tried a radically low-carb approach and gotten on stage in worse condition and with less muscle mass. I generally like to tell people that just because something was a certain way, doesn’t mean that’s the way it should be.

While carbohydrates are not technically an essential nutrient in the human diet, research and anecdotes suggest that they have their place in optimizing your physique and performance. So let’s take a look at how carbohydrates can help while trying to lose fat.

Low carb fat loss

Why metabolic rate drops while cutting

When a physique competitor (or anybody for that matter) is looking to shred off unwanted fat one of the most crucial things to be wary of is depressing metabolic rate. When you restrict energy intake aggressively your body compensates by lowering its energy output (i.e. metabolic rate slows). This is your body’s basic survival mechanism for periods of energy deprivation, since obviously it would be counterproductive to health and longevity to be expending a lot of energy while not replenishing yourself with proper nourishment.

The most notable underlying physiological mechanisms that cause metabolic rate to drop during periods of energy deprivation are lowering of thyroid hormones and the adipokine leptin. Reason being is that a thyroid hormones act on nearly every cell in the body to increase metabolic rate, therefore a decrease in thyroid hormone levels is indicative of a slower metabolic rate. Leptin also acts as regulator of metabolic expenditure but also has implications on caloric intake so lower leptin is another red flag of a slower metabolic rate.

Why carbs are helpful during a cutting phase

So this is where those trusty sugar molecules that we call carbohydrates come into play since carbohydrates specifically have significant stimulatory effect on thyroid function, leptin production and thus overall metabolic rate. [1,2,3]

This is actually the primary reasoning that many health and fitness enthusiasts who go on long cutting diets incorporate interspersed phases of carbohydrate “re-feeding” to help revive their slower metabolism and hormone production.

Another major factor to consider when on a cutting diet is maintaining muscle tissue. When someone is cutting, they’re trying to improve body composition by lowering body-fat and maintaining as much muscle as possible (since you will inevitably lose some muscle mass). However, hear is yet another reason to maintain an intake of carbohydrates in your diet while cutting since carbohydrates are highly protein sparing nutrients.

The protein-sparing effect of carbohydrates is crucial to conserving muscle tissue during periods of energy deprivation since glucose acts an energy source and lessens the amount of amino acids that are metabolized for energy. Moreover, insulin is a highly anabolic hormone and carbohydrates (except for fructose) are inherently insulinogenic. Numerous studies have verified that the muscle protein synthesis response to a nominal dose of amino acids can be enhanced by the presence of an increased insulin response. [4,5]

For these aforementioned reasons, the most prudent solution for someone looking to lose their “spare tire” while maintaining their hard-earned muscle tissue is to keep carbohydrates in the diet, if not continuously then at least intermittently through re-feeds or carb cycling (for more on this method read here).

Below we will take a look at some sample cutting diet plans that use a static carbohydrate intake.

Low Carb Eating

Setting up a cutting diet and incorporating carbohydrates

Given the multitude of variables that go into determining the optimal diet for each individual, there is no “perfect” all-inclusive diet plan that we should all follow. That being said, using the tools and suggestions laid out below you should be able to setup your own effective cutting diet that incorporates all three macronutrients and doesn’t restrict you from eating carbohydrates.

Below are the necessary steps to take to calculate your personal energy needs and macronutrient intake. This will be the baseline set for people who prefer a static intake of carbohydrates every day of the week. I will cover how to manipulate your macronutrient and calorie intake should you choose to do a re-feed protocol.

The general rule of thumb for people who are looking to lose fat is to aim for roughly a 500-calorie deficit each day. However, this may differ for some individuals depending on their physiological tendencies and other factors.  Also, if you do decide to go the re-feed route, it is likely that you will have altered calorie intake throughout the week.

After calculating your energy needs with the BMR calculator, we set your protein needs. After that we move onto carbohydrate demands (which will be largely dependent on your individual insulin sensitivity). Then finally, once protein and carbohydrate intake is set, you fill in the rest of your caloric needs with fats.

Here’s an example of how this would work for someone with 150lbs of lean body mass on a 2000-calorie cutting diet:

  • Determine your caloric needs using this M&S BMR calorie calculator
  • Set protein intake at 1g/lb of lean body mass: 150g protein per day
  • This individual is moderately insulin sensitive so we’ll set his carbohydrate intake at 1.5g/lb of lean body mass: 225g carbohydrate per day
  • Since carbohydrates and proteins contain 4 calories per gram, then we have (150+225) x 4: 1500 calories from proteins and carbohydrates
  • Therefore, this individual’s fat intake will come from the leftover calories to reach 2000: 2000-1500=500 calories/9 calories per g of fat=~55-56g of fat per day

So if this individual was on a static cutting diet, they would eat 2000 calories each day of the week composed of 150g protein, 225g carbohydrates, 55g fat. The specific macronutrient and calorie breakdown is ultimately up to the individual in question. Just make sure to eat a balance of all three macronutrients at each sitting.

Here’s a few sample meal plans for this individual based on a varying amount of meals and keeping a majority of the carbohydrate intake around the training timeframe:

**Macronutrient breakdown given as grams of protein/carbohydrate/fat, respectively**

Shredded Bodybuilder

3 Meals per day with PM workout
  • Meal 1—50/65/20
  • Meal 2—50/80/20
  • Train
  • Meal 3—50/80/15
5 Meals per day with PM workout
  • Meal 1—30/50/15
  • Meal 2—30/25/10
  • Meal 3—30/60/10
  • Train
  • Meal 4—30/65/10
  • Meal 5—30/25/10
4 Meals per day with AM workout
  • Meal 1—40/60/15
  • Train
  • Meal 2—35/70/10
  • Meal 3—35/55/10
  • Meal 4—40/40/15

Should I be concerned with what carbohydrate sources I eat and the glycemic load?

Naturally, many people are probably wondering what type of carbohydrate to eat is “the best”; well, the short answer is there is no one, single carbohydrate source that is best in all situations. Some people may have food allergies that prevent them from eating certain grains so obviously it would be foolish for them to try and wheat, for example, if they had Celiac disease.

Allergies aside, there really isn’t too much to fret about when it comes to carbohydrate source so long as you’re taking in sufficient dietary fiber and micronutrients and keeping simple sugars within reason (<20-25% of total carbohydrate intake).

As far as the glycemic load goes, I usually tell people to not read too much into it because when you’re eating balanced meals that contain fiber, unsaturated fatty acids, leafy vegetables, protein, etc. the glycemic load of your carbohydrate source will be greatly altered (attenuated) due to slower digestive rate. Thus, the glycemic index in and of itself is not very practical when eating a complete, balanced meal.

Also as mentioned earlier, insulin is not the villain while on a cutting diet (or any diet for that matter). We want carbohydrates to increase insulin somewhat when we take in protein/amino acids because the muscle protein synthetic response will be enhanced beyond that of eating just protein alone. However, this doesn’t mean you need to “spike” insulin levels with absurd amounts of simple carbohydrates like dextrose to achieve this benefit.

Concluding thoughts and the practicality of balanced diets

One point I always tend to push when people ask questions about dieting, and specifically diets that restrict one macronutrient to a high degree, is that your diet should ultimately be practical and something you will actually stick to. I don’t care how optimal something is in research or theory, if it’s not practical/applicable in real life, it doesn’t mean a damn thing in the grand scheme of it all.

This is why I am generally opposed to restrictive, unbalanced diets. Nobody wants to go about their daily life having to worry about whether or not they can eat a food because it contains carbohydrates or fats or whatever other nutrient they’re unfoundedly afraid of. Your diet is ultimately a big part of your life, you shouldn’t have to suffer or not enjoy the foods you eat just to achieve the body you want…There is a middle ground.

The idea that you have to “sacrifice to win” is taken a bit too far when you start to deprive yourself and hate the food you’re eating. I hope after reading this article you come to terms with the fact that balanced, calorie-controlled diets can work wonders for not only losing fat, but also your emotional connection with the foods you eat.  If you think it makes you “more hardcore” to eat six monotonous meals of chicken breast and broccoli all day then have at it…Reality is you’re living in a delusional world that has taken the idea of optimal dieting to a ridiculous extreme. The truth is you can have your cake and eat it too if you’re smart about it.

References:

1) Jenkins, A. B., Markovic, T. P., Fleury, A., & Campbell, L. V. (1997). Carbohydrate intake and short-term regulation of leptin in humans.Diabetologia, 40(3), 348-351.

2) Dirlewanger, M., Vetta, V. D., Guenat, E., Battilana, P., Seematter, G., Schneiter, P., ... & Tappy, L. (2000). Effects of short-term carbohydrate or fat overfeeding on energy expenditure and plasma leptin concentrations in healthy female subjects. International journal of obesity, 24(11), 1413-1418.

3) Mathieson, R. A., Walberg, J. L., Gwazdauskas, F. C., Hinkle, D. E., & Gregg, J. M. (1986). The effect of varying carbohydrate content of a very-low-caloric diet on resting metabolic rate and thyroid hormones. Metabolism, 35(5), 394-398.

4) O'Connor, P. M., Bush, J. A., Suryawan, A., Nguyen, H. V., & Davis, T. A. (2003). Insulin and amino acids independently stimulate skeletal muscle protein synthesis in neonatal pigs. American Journal of Physiology-Endocrinology And Metabolism, 284(1), E110-E119.

5) Kimball, S. R., Jurasinski, C. V., Lawrence, J. C., & Jefferson, L. S. (1997). Insulin stimulates protein synthesis in skeletal muscle by enhancing the association of eIF-4E and eIF-4G. American Journal of Physiology-Cell Physiology, 272(2), C754-C759.