Tyler Robbins Fitness

B.Sc. Biochemistry, Certified Strength and Conditioning Specialist (CSCS), Certified CrossFit Trainer (CCFT/CF-L3), USA Weightlifting Level 1

Carbs are not evil!

It's just so simple, cutting carbs, or restricting your carbs to a certain amount (If it fits your macros - IIFYM) is the key to fat loss and getting that toned, defined body, correct? Well, not exactly. Low-carb diets should be added to the same category as "dietary fats cause body fat." Now that most individuals probably realize that dietary fats don't cause excess body fat - only excess calories do, we should also explain that carbohydrates don't cause weight gain or excess body fat - only excess calories do.

*NOTE* - yes, it is entirely possible and a common practice for physique and figure competitors to low-carb their way to a defined body. Keep in mind that they use this as a short-term solution to prepare for competition and should not be, and is not, a common practice year-round outside of competition prep. Just because a low-carb diet is effective in trimming down excess body fat and defining muscles, this is not the only way to lose weight and define, nor is it a long-term solution to effective weight management.

*NOTE* - I am not saying eat all the carbs you want, either. In fact, I don't think carbohydrates should be the cornerstone of your diet - protein should be (more on that later). Instead, just realize that there is a lot of benefits to be had from eating carbs. Keep in mind that not all carbs are created equal, so eating fruits, vegetables, grains, and starches (yes, even delicious and healthy white potatoes) far surpass simple sugars such as processed additives and sweets in the overall health department.

Don't believe me? Check out this recently published study:

Energy expenditure and body composition changes after an isocaloric ketogenic diet in overweight and obese men.Abstract

BACKGROUND: 

The carbohydrate-insulin model of obesity posits that habitual consumption of a high-carbohydrate diet sequesters fat within adipose tissue because of hyperinsulinemia and results in adaptive suppression of energy expenditure (EE). Therefore, isocaloric exchange of dietary carbohydrate for fat is predicted to result in increased EE, increased fat oxidation, and loss of body fat. In contrast, a more conventional view that "a calorie is a calorie" predicts that isocaloric variations in dietary carbohydrate and fat will have no physiologically important effects on EE or body fat.

OBJECTIVE: 

We investigated whether an isocaloric low-carbohydrate ketogenic diet (KD) is associated with changes in EE, respiratory quotient (RQ), and body composition.

DESIGN: 

Seventeen overweight or obese men were admitted to metabolic wards, where they consumed a high-carbohydrate baseline diet (BD) for 4 wk followed by 4 wk of an isocaloric KD with clamped protein. Subjects spent 2 consecutive days each week residing in metabolic chambers to measure changes in EE (EEchamber), sleeping EE (SEE), and RQ. Body composition changes were measured by dual-energy X-ray absorptiometry. Average EE during the final 2 wk of the BD and KD periods was measured by doubly labeled water (EEDLW).

RESULTS: 

Subjects lost weight and body fat throughout the study corresponding to an overall negative energy balance of ∼300 kcal/d. Compared with BD, the KD coincided with increased EEchamber (57 ± 13 kcal/d, P = 0.0004) and SEE (89 ± 14 kcal/d, P < 0.0001) and decreased RQ (-0.111 ± 0.003, P < 0.0001). EEDLW increased by 151 ± 63 kcal/d (P = 0.03). Body fat loss slowed during the KD and coincided with increased protein utilization and loss of fat-free mass.

CONCLUSION: 

The isocaloric KD was not accompanied by increased body fat loss but was associated with relatively small increases in EE that were near the limits of detection with the use of state-of-the-art technology.

I have actually written about this study previously, and even linked to the video of Dr. Hall (lead author) explaining the results.

Now that the study is published, I figured it was definitely worth a re-share to explain its significance. Sure, no single study should ever be total proof or evidence of the truth, but it certainly sheds some light on common beliefs or misconceptions that I continually see in the nutrition industry.

Insulin has been the scapegoat in this whole debacle. We are constantly inundated with news of rising type-II diabetes rates worldwide, and since insulin is such a key factor when it comes to the development of diabetes, not to mention the apparent link to obesity, the rise in low-carb or no-carb diets is becoming more and more popular.

What this study shows us is that sure, low-carb participants not only experienced weight loss, but actually experienced greater weight loss than their controlled carbohydrate study counterparts. Greater weight loss is better, right? Well, no, especially not in this case. Not only did the weight loss in the low-carb camp plateau after about 3 weeks, but the greater overall weight loss can be chalked up to a loss in lean tissues (muscle) as well. So, although these individuals were losing weight (desirable), they were losing muscle as well (not as desirable).

So what should you do?

Well, if you want my honest opinion, take what I usually explain to all of my clients, friends, and family members:

  1. Eat foods that are as nutritious as possible. In other words, do your best to eliminate foods that are empty calories such as sugary beverages, etc. If the only nutrients you are getting from something carb-laden is sugar, you are doing things wrong.
     
  2. Certain carbs are very healthy and good quality sources such as potatoes, grains, beans, etc. have lots of beneficial nutrients.
     
  3. Aim to get at least 0.8-1g of protein per pound of body weight. I currently weigh around 195lbs so I aim for around 155-195g/protein/day.
     
  4. The rest of your calories then have less relevance.
     
  5. Read #3 and then #4 again.
     
  6. If you are gaining weight and you want to lose weight, you are consuming too many calories day to day. Either move more or eat less, or both.
     
  7. If you are losing weight and you want to gain weight, you are not consuming enough calories day to day. Either move less or eat more, or both.

I am personally not a fan of counting macros. Sure, I recommend clients do it short-term just to get a rough idea of where they sit, but over the long-term it can make eating feel like nothing but a chore. That time could be better spent, in my opinion, moving more and educating yourself.

Summary

  • Carbs are not evil
  • Carbs do not cause weight gain - excess calories cause weight gain
  • Carb restriction can be an effective short-term (3 weeks) solution to weight loss
  • Carbs fuel performance
  • Carb sources should be a nutrient-dense as possible