While fads in diet come and go, the low-carb trend has maintained a firm hold on the global health and wellness industry. Introduced as early as the 1860s, the method regained popularity during the 1970s in the form of the Atkins diet and again with the more recent paleo and keto dieting. The overall idea has remained mostly the same: reduce carbs to shed pounds and experience metabolic benefits.But what really happens in your body when you cut carbs completely out — even temporarily, like a week? An increasing number of individuals are giving temporary carb deprivation a try, wanting to learn how their body reacts. The outcome, however, is far more complex than expected.What Are Carbohydrates?Carbohydrates are one of the three macronutrients necessary — in addition to protein and fat — for the human body to function and be healthy in large quantities. Healthy adults, the 2020–2025 Dietary Guidelines for Americans recommend, need to consume between 45% to 65% of their daily calories from carbohydrates. These are fruits, vegetables, legumes, whole grains, and dairy — foods that also contain fiber, vitamins, and important minerals.Notably, the body cannot produce carbohydrates by itself. That is, they have to be derived from diet. So what occurs when you defy this biological makeup?Nutritionist Justin Gichaba went on social media platform Instagram, he started the challenge of eliminating all carbs for seven days and shared his experience on social media. His test revealed both the famous and lesser-known impacts of zero-carb living."I felt lighter, less bloated, and more mentally clear," Gichaba said. These short-term effects are typically reported by those who adopt low-carb diets. In fact, lower carbohydrate consumption can actually help to reduce water retention and normalize blood sugar first, which could result in greater alertness and less brain fog.Yet the advantages had boundaries. "My workouts were horrible," Gichaba admitted. "I had no energy, and my performance was awful." Without carbs, he found strength training and endurance during cardio a challenge.Why Energy Levels Take a Dip?Carbohydrates are the body's first choice as a source of rapid energy — especially useful in physical activity. When you drop carbs, however, your body resorts to using fat for energy, going into a metabolic stage called ketosis. Although ketosis can work for weight reduction, it hurts many at the expense of weakness, decreased stamina, and recovery.Carbs also help shuttle the body into rest and recovery mode after exercise. Without them, stress hormones can remain elevated longer, increasing fatigue and delaying muscle repair.As your brain primarily runs on glucose (a simple carbohydrate), depriving it of its favorite fuel source can lead to cognitive side effects. People often report feeling mentally sluggish or irritable in the first several days of carb elimination.In the early phases of ketosis, dizziness, headaches, and weakness are also experienced. These are the reactions to the metabolic change as the body learns to make ketones rather than utilizing glucose.How Does No Carbs Affect The Body?Another underappreciated effect of steering clear of carbs is a tremendous decrease in fiber intake, prevalent in whole foods like whole grains, fruits, legumes, and vegetables. Fiber is imperative in aiding digestion, ensuring daily bowel movements, and nourishing beneficial gut flora.Without fiber, most individuals on zero-carb diets are plagued by constipation, bloating, or gut dysbiosis — complications that can remain or intensify with long-term restriction.While short-term carb restriction can facilitate rapid weight loss, studies indicate that long-term compliance with very low-carb diets can be detrimental to health. A 2022 study in Current Developments in Nutrition reported that some participants on low-carb diets had a rise in LDL (bad) cholesterol, most likely because of lower fiber and higher saturated fat consumption.Other long-term hazards can include kidney stress, bone loss of density, and decreased physical function, although evidence is conflicting. Population studies have also found a correlation between very low-carbohydrate diets and increased all-cause mortality, although causation has yet to be determined.Completely eliminating carbohydrates is not only nutritionally unbalanced but frequently unsustainable. Omitting one food group can result in deficiencies and enhance the risk of disordered eating behavior.Rather, quality over quantity is recommended by experts. Not all carbohydrates are equal — leafy greens, sweet potatoes, berries, and legumes are rich in nutrients that maintain long-term health. Steer clear of ultra-processed, sugary carbs and not all carbs in general.Should You Go Carb-Free?For the average healthy person, the drawbacks of eliminating carbs outweigh any benefits — particularly in the long run. Carbohydrates play a role in brain function, digestion, muscle function, and hormonal balance. If you do want to use a low-carb diet for particular health issues, talk with a health care provider or registered dietitian so that it is done safely and in a sustainable way.A week of going carb-free can be a fun experiment, but it should not become a way of life without precise medical advice. The smarter option? Focus on whole-food, complex carbs and keep nutrition balanced.