Experts classify nutrients as “essential” because your body cannot make them, yet requires these nutrients for growth, maintenance, repair, and so much more.
“Essential nutrients are compounds that the body can’t make or can’t make in sufficient quantity,” says Mandy Ferriera. “According to the World Health Organization, these nutrients must come from food, and they’re vital for disease prevention, growth, and good health.” 
Essential nutrients can be grouped into 6 categories: Carbohydrate, protein, fat, vitamins, minerals, and water. 
- Carbohydrates, protein, and fat are macronutrients because they make up most of your diet. 
- Vitamins and minerals are micronutrients because you need them in much smaller amounts.  Smaller doesn’t mean unimportant: Deficiencies in specific vitamins and minerals can create massive problems. Interestingly, experts classify water as a micronutrient, even though you might drink liters or gallons daily. 
Carbohydrates encompass three categories: Fiber, starch, and sugar.  Among macronutrients, they frequently become oversimplified or miscategorized. Will carbohydrates make you fat, or should you make them 45-65% of your total daily calories like the Dietary Guidelines for Americans recommends? 
Experts and media reports don’t help. One day, you’ll read that the right carbs can keep you lean and healthy; the next, you’ll hear that some celebrity avoided carbs and lost 50 pounds.
Simple or Complex Carbohydrates?
To further complicated matters, dividing carbohydrates into simple or complex subcategories (as experts once did) has become outdated.
“The whole complex simple carb idea has retired to the dustbin of history,” says Mark Hyman, MD, in What the Heck Should I Eat? “What matters is how much a particular carb raises your blood sugar.”
Hyman says two slices of “healthy” whole wheat bread – a complex carbohydrate – raise your blood sugar more than eating two tablespoons of table sugar!
True, healthy carbohydrates contain more nutrients and fiber. Because your body digests them more slowly, they fill you up faster.
Sugar, on the other hand, absorbs quickly, spiking blood glucose levels to give you a short-term boost that soon leaves you crashing. 
If you’ve ever had a cola or candy bar and got a “quick fix,” but quickly felt tired (and oddly enough, craving more sugar), you know that feeling. Because sugar contains no nutrients, experts call it an “empty-calorie” food. 
Many processed foods and drinks contain more sugar than you might realize. A 12-ounce cola (small, by today’s standards) contains a whopping 10 teaspoons.  Those numbers add up quickly.
Some surveys show the average American consumes about 152 pounds of sugar and 133 pounds of flour that converts to sugar annually, says Hyman. That’s about a pound of sugar every day!
Choosing the right carbohydrates, then, becomes fundamental to having steady blood sugar levels and getting sufficient nutrients for vital health. In general, the least-processed carbohydrates make your best sources.
These nature-packaged foods – low-sugar fruits like berries as well as leafy and cruciferous greens – don’t have barcodes or ingredient lists, and they come intact with the correct ratio of nutrients.
Protein — or more accurately, the 20 amino acids your body derives from protein – provides your body the building blocks for muscle, bone, skin, hair, and so much more. 
Protein helps build hormones, enzymes, and antibodies. DNA and important antioxidants like glutathione require protein.  In fact, every cell in your body contains and requires protein.
You can understand, then, why “protein” comes from the Greek word meaning primary. Unlike carbohydrates or dietary fat, your body doesn’t sythesize these well, so we must get this macronutrient from food or supplements. 
Protein breaks down into two categories: Essential and non-essential amino acids. 
- The nine essential amino acids are those your body cannot make. You must get them from food or supplements.
- The remaining 11 amino acids your body can synthesize, making them non-essential.
- Of those 11 non-essential amino acids, six classify as conditionally essential. In other words, some people must get these amino acids from food or supplements. 
How much dietary protein you need depends on numerous factors including your age, level of physical activity, and your overall health. Certain demographics – including people with chronic illnesses, athletes, and pregnant or breastfeeding moms – require additional protein.
How Much Protein Do You Need?
Your body goes through 300 – 400 grams of protein daily, but that doesn’t mean you need that much since you can recycle used proteins.
The Institute of Medicine (IOM) recommends the average adult get about 0.36 grams of protein per pound. For a 150-pound person, that would be about 54 grams of protein per day. Some experts believe that number is too low, especially considering the numerous roles protein plays. 
Protein comes from many sources including cold-water fish, grass-fed beef, nuts, seeds, and legumes.
Whereas most animal foods contain all the essential amino acids, many plant foods are low or absent in at least one essential amino acid. Some plant proteins are also less bioavailable than animal protein.
That doesn’t mean vegans and vegetarians can’t get sufficient protein from plant foods. You just need to be more mindful and incorporate plenty of protein-rich foods like nuts and seeds.
For decades, health experts believed fat was unhealthy. After all, eating fat makes you fat, right? Not quite. As with carbohydrates, the answer is more complex.
Three Types of Fat: Saturated, Monounsaturated, Polyunsaturated
Dietary fat (scientifically called lipids) falls into three categories:
- Saturated fats are generally solid or waxy at room temperature. You mostly find them in animal products and a few oils such as coconut oil.
- Monounsaturated fats have a “heart-healthy” glow because research shows many foods rich in them (including olive oil) can reduce your risk for cardiovascular-related problems.  They contain one double bond, hence the name monounsaturated.  Many sources of monounsaturated fat are rich in the fat-soluble antioxidant vitamin E. 
- Polyunsaturated fats contain more than one double bond, making them more unstable than other fats. That fishy smell? Fish are high in unstable polyunsaturated fats, which can go rancid quickly. Polyunsaturated fats include omega-3 and omega-6 fats, which are considered essential for brain function, cell growth, and more because your body cannot make them. 
- You’ll find omega-3 fatty acids in cold-water fish, flaxseeds, and walnuts. The primary omega-3 is alpha-linolenic acid, which your body can theoretically convert to the longer-chain omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
- You’ll find omega-6 fatty acids in vegetable oils, nuts, and seeds.  The primary omega-6 is linoleic acid, which your body converts into longer-chain omega-6s. 
Very few foods contain just one type of fat. A grass-fed steak contains some saturated, monounsaturated, and polyunsaturated fat.
You Need Fat
Your body requires healthy fats for many roles, including:
- Absorbing vitamins and minerals, building cells, muscle movement, and blood clotting.
- Balancing your blood sugar levels.
- Keeping your brain operating at peak levels.
- Lowering your risk of arthritis, cancer, and Alzheimer’s disease. 
So why did dietary fat get a bad rep? That answer is complicated and involves politics as well as nutritional misunderstanding.
But fat can make you fat? Well, foods rich in dietary fat are more calorie-dense: Whereas protein and carbohydrate contain four calories per gram, fat contains nine per gram. 
Hormones, Good Fats, and Bad Fats
While too many calories can contribute to weight gain, hormones matter more. And overall, healthy dietary fat positively impacts hormones that regulate satiety and appetite. 
Some dietary fats – including saturated fat – are still hotly debated.  For these, the source matters: The saturated fat you get in healthy foods like coconut oil is different than what you eat in a fast-food cheeseburger.
Likewise, omega-3 fatty acids get classified as good while omega-6 fatty acids are bad. That’s not always the case: A few omega-6 fatty acids, like gamma-linolenic acid (GLA), are actually anti-inflammatory. 
Additionally, many healthy foods including nuts and seeds contain omega-6 fatty acids. Many of us simply eat too many omega-6 fatty acids – about 20 times more, in fact – and not enough anti-inflammatory omega-3 fatty acids.  Balance becomes key with these two fatty acids.
The one dietary fat nearly everyone agrees is bad: Trans fats. But there’s an exception within every rule: Some dairy and meats contain naturally occurring trans fats. The truly bad ones are “partially hydrogenated” fats you find in some vegetable oils and processed foods. 
Vitamins are organic compounds you require in small quantities, either because your body does not produce enough or doesn’t make that nutrient at all. 
Your body can synthesize vitamin D from sunlight, and gut bacteria produce some vitamin K, but for the most part, you need to get vitamins from food or supplements.  
Water-soluble and Fat-soluble
The 13 known vitamins fall into two categories: Water-soluble or fat-soluble. The body cannot store water-soluble vitamins, which quickly excrete in your urine and need to be replaced more often than fat-soluble vitamins. 
Many vitamins carry alternate names or come in different forms: 
- Researchers sometimes refer to vitamin C as ascorbic acid.
- Vitamin D comes as ergocalciferol (D2) or cholecalciferol (D3).
- Vitamin E comes in eight isomers: Four tocopherols and four tocotrienols.
- The 8 B vitamins work as a team, and you’ll often find all of them in a B-complex formula. 
When you read a food or supplement label, the nutrient breakdown will typically be clear as to amounts of specific vitamins. In other words, it might read “vitamin D (as D3).”
Deficiencies in any specific vitamin can create widespread problems that span from mild to life-threatening.
For instance, intaking insufficient pantothenic acid (vitamin B5) can create a “pins and needles feeling.” On the other hand, vitamin B6 deficiencies can create anemia, peripheral neuropathy, or damage to parts of the nervous system other than the brain and spinal cord.
Most vitamin recommendations come largely from guidelines set by the Institute of Medicine, which typically recommends amounts in milligrams (mg), micrograms (mcg), or until recently international units (IU). 
Some experts believe these vitamins recommendations are too low, making supplementing necessary. Even with a healthy diet, cooking, storage, and exposure to air can deactivate these fragile compounds. 
While both are micronutrients, vitamins, and minerals differ in that minerals are inorganic and hold onto their chemical structure.  This makes minerals more stable, but other obstacles, including soil depletion, mean we might not get sufficient amounts from food. 
Like vitamins, minerals support numerous bodily functions, including building and maintaining healthy bones and teeth, supporting muscle function, optimizing immunity, and energy production. 
Major and Trace Minerals
Minerals fall into two categories: Major and trace minerals. 
- Your body requires and stores large amounts of calcium, magnesium, and other major minerals. You’ll often find these in milligrams (mg).
- Trace minerals come in smaller amounts (usually micrograms or mcg), but they are equally important. Trace minerals include chromium, selenium, and zinc. 
Mineral deficiencies can create widespread problems. Take magnesium, which plays a role in over 300 enzyme systems, including protein synthesis, muscle, and nerve function, controlling blood glucose, and regulating blood pressure.  Chronic diseases, medications, and getting insufficient amounts from food are among the reasons many people are at risk for magnesium deficiencies. 
Like vitamins, minerals interact with each other. Too much of one mineral can create imbalances in another. Too much manganese, for instance, can trigger iron deficiencies.  Others, such as magnesium or chromium, perform therapeutically on their own in higher doses for specific conditions.  
You can survive for weeks without food, but water? While some experts speculate up to a week, 3 or 4 days might be more accurate.  (Note: Don’t try this science experiment at home!)
Overall, about 60% of your body is water.  Your brain and heart are about 73% water.  Muscles and kidneys, about 79%. Your skin is made of about 64% water. But the top organ? Your lungs are about 83% water.
Sufficient water intake becomes vital for nearly every bodily function. “Water can improve energy, increase mental and physical performance, remove toxins and waste from your body, keep your skin healthy and glowing, and may even help you lose weight,” says Jonny Bowden, Ph.D., in The 150 Healthiest Foods on Earth.
Your body constantly loses water via sweat, urinating, and even breathing. Dehydration can occur more easily than you might imagine, and its repercussions can jeopardize your health and even become fatal. 
How Much Water Do You Need?
How much water you require depends on numerous factors including age, gender, health status, and physical performance. The average adult man needs about 3 liters per day, whereas an adult female needs about 2.2 liters daily. 
Yes, you can get some of that from food, but you’ll want to get most from clean, filtered drinking water. 
Emphasis on clean and filtered. “There are hundreds of chemicals, pollutants, and toxic metals (mercury, arsenic, etc.) that have the potential to wind up in our water,” says Bowden.
A good rule of thumb is half your body weight in water ounces every day. If you weigh 160 pounds, that’s about 80 ounces of water. Keep a BPA-free canteen nearby filled throughout the day to meet that quota.
Essential Nutrients 101 – The Science of Why
Looking at the six essential nutrients reveals their complexity, but also underlies one particular conclusion: We often don’t typically consume nutrients in isolation. (There are some exceptions, such as taking amino acids like L-glutamine therapeutically or consuming protein powder.)
Instead, we usually consume nutrients together in food and supplements. And for the most part, the six macronutrients and micronutrients work synergistically.
While calcium often gets touted for strong bones, this major mineral works synergistically with vitamin D, vitamin K, magnesium, and phosphorus to protect your bones against fractures. 
Some vitamins and minerals — including vitamins C and E, as well as selenium — work separately and synergistically as antioxidants. 
Macronutrients also work together. You don’t usually eat protein, fat, or carbohydrates individually. You eat wild-caught salmon, which contains protein and fat. Or you eat lentils, which are mostly fiber (carbohydrate) along with protein. And of course, those foods come loaded with vitamins and minerals.
Dietary fat and protein work together to support your muscles, brain, bones, skin, and so much more.  Dietary fat helps your body optimally absorb the fat-soluble vitamins (A, D, E, and K). Along with protein, dietary fat slows the absorption of carbohydrates so you feel full longer. 
The nutrient-rich, whole foods in our Core and Advanced plans incorporate all of these nutrients in optimal amounts to stay lean and healthy. The plans differ slightly. Our Advanced Plan, for instance, includes more moderate amounts of protein and limits certain carbohydrates like higher-sugar fruit.
Even then, meeting your nutrient quota from food alone can be challenging. That means supplementing with a solid nutrient foundation may be necessary, even with an ideal diet.
Consider these foundational supplements:
- Prenatal Essentials if pregnant, considering pregnancy, or breastfeeding.
Discuss including these and/or any other additional supplements with your healthcare practitioner. Never modify any medications or other medical advice without your healthcare practitioner’s consent.