When it comes to diet and nutrition, few things are as controversial over the past decade or two than carbohydrates. Once upon a time, carbs were the foundation of the (flawed) food pyramid. Nowadays, they are “tolerated” at best by certain dietary paradigms (paleo, primal, etc.) or flat out prohibited by others (e.g. carnivore).
Further muddying the waters is that some individuals thrive on a high-carb diet, while others struggle after indulging in them.
So, what gives?!
Why can some individuals seemingly eat carbs with ease, while others seem to gain weight merely getting too close to them?
Ahead, we’ll discuss a few key factors that influence carbohydrate tolerance. Before we get there, though, let’s clear up some misconceptions about carbohydrates.
Carbs Are Not Bad (They’re Also Not Making You Fat)
Regardless of what the paleo, carnivore, and keto communities may say, the body’s primary source of energy is glucose…which also happens to be a carbohydrate. Simply put, your body is designed to run on carbohydrates, especially when you’re performing physically demanding activities, like interval training, resistance training, circuit training and other moderate-to-high intensity exercise. Furthermore, carbs are readily available and affordable (which is helpful for those of us trying to make every dollar count).[1] They’ve also played a key role in human evolution.[2]
During rest or low-level activities, our bodies primarily burn fat for fuel, but a portion of that energy also comes from carbohydrates.
Something else to consider are the types of carbohydrates you’re eating. Fruits, veggies, and whole grains are vastly different from ultra-processed carbs like candy bars, potato chips, soda, fruit juice, etc. The former contains a plethora of vitamins, minerals, complex carbohydrates, fiber, and antioxidants, while the latter group is primarily simple sugars that spike blood sugar levels and insulin without offering much in the way of satiety or micronutrient.
That being said, if you’re in a calorie deficit (even if you’re eating primarily ultra-processed foods like Twinkies) you can lose weight, simply due to the fact that weight loss and weight gain is dictated by calories in vs calories out.
Now, eating a diet that consists mostly of ultra-processed foods will likely lead you to overeat since it’s typically not high in fiber or protein, both of which help keep hunger in check, but ultra-processed foods (doughnuts, cake, french fries, etc.) aren’t just carbohydrates -- they contain high amounts of fat (which packs more calories per gram than carbs) and salt.
All of this is to drive home the point that carbs are not solely responsible for individuals gaining unwanted weight (body fat).
It is entirely possible to eat a diet that’s higher in carbohydrates, yet still build muscle, lose weight, and support cardiometabolic health. That being said, there are some factors to consider when deciding how many carbohydrates an individual can/should eat each day.
Why Some People Can Eat More Carbs
Genetics Play a Role
Our genetic makeup significantly influences how our bodies process carbohydrates. Some individuals inherit genes that allow them to metabolize carbohydrates more efficiently, thereby limiting potential “negatives” of carbohydrates, such as blood sugar spikes or energy crashes.
Insulin Sensitivity
Insulin is an important hormone for nutrient partitioning and blood sugar regulation. It helps to shuttle glucose from the bloodstream into tissues where it can be stored, such as skeletal muscle or the liver.
Insulin, like carbohydrates, has been unfairly demonized over the past several decades, but the reality is that insulin plays a big role in supporting muscle growth and recovery as well as overall cardiometabolic health.
Individuals with better insulin sensitivity are able to manage higher carb intake better than individuals with poor insulin sensitivity as well as those that are insulin resistant. That being said, there are several factors that impact insulin sensitivity, including our next talking point…
Activity Level
Above, we mentioned that carbohydrates are the preferred source for our cells, especially during physical activity. What this means is that individuals with higher physical activity levels need more carbohydrates. They also have better insulin sensitivity.
On the flip side, sedentary individuals might not need as many carbs since the demand for energy from their muscles is lower. So, if you like eating carbs, make sure to stay active!
Microbiome Influence
The amount of research focused on the gut microbiome that has been published in recent years is staggering. We continue to learn just how impactful and far-reaching the GI system has on various facets of our life, including mood, athletic performance, cognitive function, immune function, and even the appearance of our skin!
The bacteria in our gut significantly affect how we digest food, including carbs. At the same time, the foods we eat also influence the health of our gut microbiome. Fiber, the indigestible portion of plant foods (carbohydrates), serves as an important food source for gut bacteria. This means that not consuming enough fiber may adversely affect the diversity and quantity of good gut bacteria (aka probiotics).
The good news is that the best natural sources of fiber are found in carbohydrate-rich foods, including fruits, veggies, whole grains, nuts, seeds, and legumes! For added support, you can also use a daily fiber supplement, such as 1UP Fiber Plus which supplies 7 grams of fiber per serving.
Dietary Choices
The types of carbohydrates that make up the majority of your daily carb intake also matter. Less-processed (“natural”) carb-rich foods like fruits, veggies, whole grains, nuts, seeds, and legumes contain fiber, which slow the release of carbohydrates into the bloodstream, which promotes stable energy levels and better hunger management.
What you eat alongside your carbs is important, too. Protein and healthy fats also help slow digestion, which can help stabilize blood sugar levels, making it easier for some individuals to include higher amounts of carbohydrates in their meals.
On the flip side, diets high in ultra-processed foods and refined sugars are typically low in fiber, protein, and healthy fats, which can lead to overconsuming calories (and subsequent weight gain).
Note: Having a little bit of junk food in your diet is fine, provided you are staying physically active and eating a mostly nutritious diet. Simple carbs also have their place immediately before, during, or after a tough workout or competition as they can help to replenish muscle glycogen and support recovery. This is one reason why we’ve created 1UP Tri-Carb!
Age
Our bodies change as we age (this isn’t any big secret). Recovery slows down, gray hairs spring up, and hormone levels change. The age-related hormonal fluctuations can impact metabolism as well as how our bodies handle foods (especially carbs). While Father Time is undefeated, one of the best things you can do to support healthy aging is to stay physically active and maintain a healthy body composition -- both of which support insulin sensitivity and your ability to consume carbohydrates.
Personal Preference
Last, but not least, we need to address personal preference when it comes to carbohydrate intake. Some individuals enjoy eating a higher amount of carbohydrates in their diet, while others enjoy a higher proportion of protein and fat.
It’s also worth mentioning that some people naturally have a soft spot (“weakness”) for high-carb foods, which can lead them to overeat. In this instance, these individuals may benefit from restricting carbohydrates if they’re interested in maintaining a certain body weight or cardiometabolic marker.
The Bottom Line
Carbohydrates are the preferred source of energy for our cells, especially during exercise. Genetics, activity levels, age, personal preference and overall diet all factor into why some people can eat more carbs than others.
Understanding these factors can help you decide how to structure your diet for your fitness, physique, and overall health goals.
And, if you need help figuring out the right amount of carbs, protein, fat and/or calories to meet your goals, we’re here to help!
The 1UP Fitness App offers customized calorie goals (and training plans!) for FREE!
References
- National Research Council (US) Committee on Diet and Health. Diet and Health: Implications for Reducing Chronic Disease Risk. Washington (DC): National Academies Press (US); 1989. 9, Carbohydrates. Available from: https://www.ncbi.nlm.nih.gov/books/NBK218753/
- Hardy, K., Brand-Miller, J., Brown, K. D., Thomas, M. G., & Copeland, L. (2015). The Importance of Dietary Carbohydrate in Human Evolution. The Quarterly Review of Biology, 90(3), 251–268. https://doi.org/10.1086/682587
