​Simply cutting carbs and fat is not a guarantee for losing weight

What are the nutrients that form the base of a healthy diet? Food contains the building blocks you need to develop and maintain your body, supplying energy and raw materials so that organs, tissues, and cells are powered to work and renew 24/7. No fuel, no you.

It’s important to know how food is built and how it works because its effect, function, and composition aren’t the same from bite to bite. And its behavior is certainly not the same once it passes from your mouth to your digestive system. Here, we’ll cover the three main types of foods we need a lot of in our diets—called macronutrients—and how they’re broken down and used in the body.

Macro vs. micronutrients

The task of fueling you is achieved through a cocktail of components that mostly come in the form of carbohydrates and fats (used for energy) and proteins (the building blocks of the body). These are called macronutrients because we need them in large amounts.

Food also includes other necessary elements, known as micronutrients, which include vitamins, minerals, phytochemicals, and antioxidants. Together, macro and micronutrients help dictate your overall well-being, including your weight, your waist size, and your overall health risks.

Keep in mind that although it may seem simple to classify particular foods as proteins, carbs, or fats, the reality is that most foods include a combination of macronutrients (fish has protein and fat; beans have protein and carbohydrates). You don’t have to do complex calculations every time you eat, but understanding why certain foods are good sources of macronutrients helps use them to your advantage.

Carbohydrates 

This hot-button macronutrient tends to elicit an immediate reaction, dividing the diet industry into two camps: haters and embracers. Whether you see an energy source or think weight gain, let’s start with a little science.

Put simply, carbs are sugars—but not in the sense you might think. Sugar is a chemistry term for certain types of molecules. Because there are many forms of sugar molecules, there are many forms of carbohydrates. The main ones are simple sugar, starch, and fiber. The most basic building block of these is a sugar molecule, which the body can break down and turn into glucose, our main energy currency.

Glucose provides quick fuel as soon as it’s available in the bloodstream. Insulin, which the pancreas secretes, sends that glucose into your cells to be used for energy. Glucose isn’t stored, so if it is not immediately used, it is converted into a substance called glycogen. Glycogen is a form of medium-term energy stored in your liver and muscles; your body can call on it as needed and can reserve about two days’ worth.

Although your body relies on carbohydrates for energy, it’s better to obtain that from complex carbohydrates rather than simple ones. Simple sugars—for example, those found in table sugar, white flour, and cornstarch—supply instant energy but wreak biological havoc on many of your inner systems.

Complex carbohydrates—for example, whole grains and fiber—are broken down by the body more slowly, so the sugars are released gradually into the blood. This way of supplying energy provides for a calmer, more efficient functioning of your bodily systems. Thus, fruits, vegetables, beans, and whole grains are carbs to cultivate, while processed foods, baked goods, and other “white carbs” are ones to avoid.

Fats 

Fat was long misunderstood. Experts believed that fat in food equaled fat on the body. Thank goodness, that dogma has changed. Today, many people realize that fat (the macronutrient kind) should be thought of as a component of food, one that has a variety of chemical interactions.

Used for long-term storage of energy, fat contains more than double the energy of carbohydrates (2.25 times, to be exact). It comes in two forms: saturated and unsaturated.

Saturated fats are solid at room temperature and are typically derived from animal products (coconut and palm oils are exceptions as plant-derived saturated fats). These are the least healthy kinds of fats and are associated with increased inflammation and increased low-density lipoprotein (LDL) or “bad” cholesterol. Worse, they come with proteins that change the bacteria in the gut to make them produce inflammation throughout the body. Recent studies suggest that saturated fat also may increase the risk of insulin resistance.

Proteins

Proteins are truly the main building blocks of life. They are made up of amino acids that, like metal, can be combined into wide varieties of machines that the cells of your body need to run. Although most people think of meat as protein, all cells contain a lot of it—even the ones in celery. The big difference between the proteins in plant cells and animal cells is the amino acids; animal proteins contain a wider variety of amino acids. Vegetarians should eat a wide variety of foods to receive the full mix.

Although high-protein diets are all the rage, we don’t recommend eating more than the average American already eats—about 82 grams a day, the amount in 10 ounces of a grilled chicken breast. Eating too much protein can lead to weight gain, and diets very high in protein can stress the kidneys.

Why food matters

This all begs the question: How do you get fat? Any of the macronutrients—fat, carbs, and protein—can cause you to gain weight if you eat too much. Because fat is the most energy-dense of the three macros, eating a lot of it can quickly lead to too many calories in and not enough out.

What your body cannot use for energy, or fit into those limited glycogen stores, will be stockpiled as fat that your body wants to keep in case you run out of energy.

The fat that surrounds your organs, called visceral fat, is more dangerous to your health than fat stored under the skin, called subcutaneous fat. Visceral fat has been linked to metabolic disturbances like insulin resistance and type 2 diabetes, as well as increased risk for cardiovascular disease and dementia.

The million-dollar question is how do you get rid of the fat? Your body wants to use glucose as fuel first because fat is better for long-term storage. You’re always using a combination of both, but to burn more fat than glucose, you need to burn through your sugar stores and get to the fat.

And how do you do that? Eat earlier in the day and only in the day; avoid eating after dark; and don’t overeat.