What happens if humans don't eat carbs? The physiological effects and long-term health impacts
                                
                                
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                                    5 min read                                
                            
                                Carbohydrates are the body's primary and preferred source of fuel, with roughly 45 to 65% of an average person's daily calories coming from this macronutrient. When these vital fuel sources are removed, the body is forced to undergo a significant metabolic adaptation to find an alternative energy supply.