Do some people need less carbs? The answer is yes.

November 22, 2025 •

5 min read

According to the Dietary Guidelines for Americans, carbohydrates should comprise 45-65% of daily calories for most people, but this 'one-size-fits-all' approach is not optimal for everyone. Individual factors such as genetics, metabolic health, and activity level significantly influence whether some people need less carbs to thrive. Understanding these personal differences is key to optimizing your health and energy levels.

Quick Summary

This article explores the personalized nature of carbohydrate needs, discussing how genetics, metabolic conditions like insulin resistance, and physical activity levels can determine an individual's ideal intake. It details how to identify your unique requirements for optimal health.

Key Points

Genetic Factors: Your genes, such as AMY1 and APOE, can influence how efficiently your body metabolizes carbohydrates, meaning some people are naturally more suited to lower carb diets.
Insulin Resistance: Individuals with insulin resistance or prediabetes may need to significantly reduce their carbohydrate intake to improve blood sugar control and insulin sensitivity.
Activity Level: A sedentary person needs fewer carbohydrates than an endurance athlete, who relies on carbs to fuel high-intensity and prolonged exercise.
Carbohydrate Quality: Focusing on high-fiber, whole-food carbohydrate sources is beneficial for everyone, but especially for those with lower carb tolerance.
No One-Size-Fits-All: There is no universal amount of carbohydrates that suits everyone, and individual needs are determined by a complex combination of genetics, metabolic health, and lifestyle.
Personalized Approach: The most effective nutritional strategy involves listening to your body and adjusting carbohydrate intake based on your unique metabolic and physical needs.

The Case for Individualized Carbohydrate Needs

For decades, mainstream nutrition has focused on broad guidelines for macronutrient intake, yet a growing body of scientific evidence reveals a more complex picture. The idea that 'do some people need less carbs?' is no longer a fringe theory but a reflection of the intricate interplay between an individual's biology and their diet. While carbohydrates are an essential energy source, especially for high-intensity exercise, the amount and type required can vary drastically from person to person. This shift toward personalized nutrition considers multiple factors that dictate how efficiently the body processes and utilizes carbohydrates.

Genetic Variations and Carbohydrate Metabolism

One of the most compelling reasons behind varying carbohydrate needs lies in our genetic makeup. Genes play a significant role in how our bodies react to different types and amounts of carbohydrates, influencing everything from blood sugar regulation to overall metabolic health. Several studies have identified specific genetic variants that affect carbohydrate metabolism:

AMY1 Gene: This gene produces salivary amylase, an enzyme that starts the digestion of starch in the mouth. Individuals with a higher number of AMY1 gene copies may be better equipped to digest starches and may not need to restrict carbs as much as those with fewer copies.
FTO Gene: Known as the 'fat mass and obesity-associated gene,' variants of the FTO gene have been linked to an individual's tendency for weight gain, often influenced by dietary choices. Some variants are more sensitive to high-carb diets, suggesting that individuals with these markers might benefit from a lower carbohydrate intake for weight management.
APOE Gene: Variations in the APOE gene can affect cholesterol levels and metabolic responses to different macronutrient ratios. For instance, certain variants (APOE2) may make individuals more suited to lower-carbohydrate, higher-fat diets, while others (APOE4) respond better to higher-carb, low-fat diets.

Metabolic Conditions and Insulin Resistance

For many, metabolic health issues like insulin resistance are a key driver for needing to reduce carbohydrate intake. Insulin resistance occurs when the body's cells don't respond well to insulin, leading to elevated blood glucose and insulin levels. This can create a problematic cycle where the body struggles to process carbohydrates effectively.

For individuals with insulin resistance, consuming a diet high in processed carbohydrates and sugars can exacerbate the condition. While eating healthy, whole-food sources of carbs is generally better, portion sizes are also crucial. In these cases, reducing carbohydrate load can be a highly effective strategy for improving insulin sensitivity and blood sugar control. This is particularly relevant for those with prediabetes, type 2 diabetes, or metabolic syndrome.

Physical Activity Levels and Fuel Requirements

The amount of carbohydrates an individual needs is directly tied to their physical activity level. A sedentary person has much lower energy demands and, therefore, can function optimally on a lower carbohydrate intake. In contrast, highly active individuals and endurance athletes require a substantial amount of carbohydrates to fuel their performance and replenish glycogen stores.

High-Intensity Exercise: During intense, prolonged exercise (e.g., a marathon), carbohydrates are the primary fuel source. Athletes often follow specific carb-loading and in-race fueling strategies to ensure glycogen stores are sufficient to prevent fatigue. Recommendations for extreme endurance can be as high as 8-12 grams of carbs per kilogram of body weight per day.
Lower-Intensity Exercise and Sedentary Lifestyles: For those engaged in less intense or shorter-duration activity, the body can more readily rely on fat stores for energy. In these cases, a lower carbohydrate diet may be perfectly suitable, and can even help promote better metabolic health. A person doing light exercise (e.g., a 30-minute daily walk) needs far fewer carbs than a cyclist training for a multi-hour race.

Factors Influencing Individual Carb Tolerance: A Comparison


Factor	High-Carb Tolerant Individuals	Low-Carb Favorable Individuals
Genetics	Higher AMY1 gene copies, specific APOE variants	Lower AMY1 gene copies, specific APOE variants, FTO gene sensitivity
Metabolic Health	High insulin sensitivity, no history of metabolic syndrome or T2D	Insulin resistance, prediabetes, T2D, or metabolic syndrome
Physical Activity	Elite endurance athletes, individuals with high-volume training schedules	Sedentary lifestyle, light recreational exercise, less intense activity
Body Composition	Generally lean with efficient glucose utilization	Excess body fat, particularly visceral fat
Lifestyle	High energy expenditure through daily movement	Less active lifestyle, often combined with a high intake of refined carbs

Making it Work for You: A Practical Approach

Given the individualized nature of carbohydrate tolerance, a personalized approach is the most effective. Instead of adhering strictly to universal dietary guidelines, individuals should consider their unique metabolic profile, genetic predispositions, and lifestyle to determine their optimal carbohydrate intake.

Prioritize Quality: Regardless of your carb needs, focus on whole, unprocessed sources. Choose fiber-rich vegetables, fruits, and whole grains over refined carbohydrates, added sugars, and processed foods.
Monitor Your Body's Response: Pay attention to how your body reacts to different carbohydrate levels. Symptoms like energy crashes, mood swings, or persistent hunger after eating can indicate that your current intake is not working for you.
Adjust Based on Activity: Match your carbohydrate intake to your activity levels. On days with intense workouts, increase healthy carb consumption. On more sedentary days, a lower carb intake may be more appropriate.
Consult a Professional: A registered dietitian can provide personalized guidance based on your health history, goals, and lifestyle. For individuals with conditions like type 2 diabetes or severe insulin resistance, a healthcare provider can help manage dietary changes safely.

Conclusion: Understanding Your Unique Needs

The question of 'do some people need less carbs?' has a definitive 'yes' for an answer, highlighting the critical importance of personalized nutrition. A combination of genetics, metabolic state, and physical activity creates a unique nutritional blueprint for every individual. Recognizing this can empower you to move beyond generic dietary advice and discover what truly works for your body. By listening to your biological signals and making informed choices about carbohydrate quality and quantity, you can optimize your health, energy, and well-being. Ultimately, there is no single right diet for everyone; the best approach is one tailored to your specific needs.

Authoritative Link

For a deeper dive into the metabolic effects of very-low-carbohydrate diets, explore the research available on the NCBI Bookshelf here: Metabolic Effects of the Very-Low-Carbohydrate Diets

Frequently Asked Questions

Insulin resistance is a condition where the body's cells do not respond effectively to insulin, causing blood glucose and insulin levels to rise. This can make it difficult for the body to process carbohydrates efficiently, so individuals with insulin resistance may benefit from reducing their carbohydrate intake to improve insulin sensitivity and blood sugar control.

Yes, genetic factors play a significant role in how your body metabolizes carbohydrates. Variants in genes like AMY1 and APOE can influence your ability to digest starches and affect your metabolic response to different carb-to-fat ratios. Genetic testing can provide insights, though the overall effect is modest.

Endurance athletes need more carbohydrates because high-intensity and prolonged exercise relies heavily on glycogen stores for fuel. Consuming a high-carb diet helps replenish these stores, which can be depleted within 90-120 minutes of hard activity. Sedentary individuals have lower energy demands and can rely more on fat for fuel.

If a high-carb diet is not a good fit, you might experience symptoms such as persistent fatigue, sugar cravings, energy crashes after meals, weight gain, or difficulty managing your blood sugar levels. These are all potential indicators of poor carb tolerance.

Not necessarily. While reducing carbohydrates can be highly effective, the best approach depends on the individual. A moderate carbohydrate intake focused on high-quality, whole-food sources and balanced with sufficient protein and healthy fats may be equally beneficial. Professional guidance can help determine the right balance.

Both the type and amount of carbohydrate are important. High-fiber, complex carbs from whole foods are generally better for blood sugar stability and overall health than refined, processed carbohydrates. However, the total quantity still plays a role, especially for those with insulin resistance.

Completely eliminating carbs is not recommended without medical supervision, as a balanced diet is important for most people. A better approach is to prioritize whole-food carbohydrates and reduce your intake of processed and refined sugars to see how your body responds. Any major dietary change should be discussed with a healthcare professional.