Relationship Between Your Body and Nutrition
The relationship between your body and nutrition may be best understood by looking at carbohydrates, proteins and fat as different types of fuel for the same machine.
An automobile requires gasoline, electricity and oil to work properly. Oil lubricates the engine's moving parts, a battery provides charge to start the engine and gasoline provides the primary source of fuel to keep the motor running.
Forms of Body Fuel
Different size automobiles have different requirements regarding the types and amounts of fuel used. Also, the harder the engine has to work, the more fuel will be required. Your body is no different - fats, proteins and carbohydrates are all types of fuel in the form of calories that serve specific purposes within your body.
Among other things, protein is needed to repair tissue, fats lubricate your joints and carbohydrates serve as your body's primary source of fuel. Every person has different nutritional requirements. Considerations such as age, activity level, body composition and medical conditions all factor into one's energy requirements.
Getting back to our automobile analogy, your car has recommended levels for each fuel source. For example, your engine may optimally require five quarts of oil to run properly and trying to add more than that may harm the engine. Your engine may be able to function at less than an optimal level, such as four quarts, but if the oil level is too low, your engine will seize and cease working.
Understanding Nutrition and Macronutrients
The same can be said with any of the macronutrients that provide your body with calories. All three have a caloric value and can be burned as fuel, but each one serves a specific purpose within your body. Your body requires a minimal amount of each daily to function properly and if those needs are not met, your health and performance will suffer.
Too little protein and your body will have a hard time repairing muscle tissue and healing wounds. Too little fat will inhibit hormone production and lead to sore joints and dry skin. And, if your carbohydrates are too low, muscle growth will be inhibited and your body will have to use dietary fat and protein as fuel sources, interfering with their other purposes.
Most people notice a difference with their cars performance if they use high quality fuel sources, as opposed to discount products. Can you imagine a Formula-1 racecar pulling into a discount gas station before a race to fuel up? No way! Just as all fuels are not created equal, all foods are not of the same vein.
Even though one gram of carbohydrate contains four calories regardless of the source, the difference in how your body utilizes 20 grams of carbohydrates from table sugar and the same amount from oatmeal are significant, due to the effect carbohydrates have on blood sugar levels. A rapid rise in blood sugar, followed by an equally rapid drop can affect mood, cravings and physical performance. Yet, both 20-gram servings contain the same number of calories (80).
The same can be said for different types of fat. At nine calories per gram, fat is calorically denser than either carbohydrates or protein. But, the differences between saturated and unsaturated fats play a very important role in a person’s health. A tablespoon of olive oil may help improve cholesterol levels, while the same amount of butter may have the opposite effect.
Finally, different sources of protein have different levels of effectiveness with regard to how your body will utilize it. At four calories per gram, protein plays an important role in muscle growth and helps maintain muscle mass on a calorie-restricted diet. Many studies show that animal protein sources are much more effective for these purposes than plant-based proteins.
Maximizing Your Body Fuel
Your body burns calories 24 hours per day. Of the total number of calories your body burns on an average day, 60-65 % is used for life support. Maintaining your normal temperature, respiration, circulation and maintenance, all require calories. Digestion can burn another 10% and physical activity can burn the remaining 25-30% of your daily calories. If you reduce your caloric intake or increase your energy expenditure, you body can use body fat as fuel, provided your calorie provide your body with the proper macronutrient amounts. But, consuming too few calories will signal your body to use the more nutrient-dense muscle tissue as fuel, which will cause your body to burn fewer calories. A severe restriction will actually cause your body to burn fewer calories for fear of starvation.
Finding The Right Balance
Your body requires calories in order to burn calories and you need to provide your body with calories from all three macronutrient sources. Just as you would not put excess oil in your engine to make up for a lack of gasoline, you shouldn't deprive your body of any of its nutrition needs to create a desired effect. Carefully, plan your diet with enough calories from quality sources to help you reach your weight-loss or increased lean mass goals.