Our bodies need energy for normal functioning, repair, growth, and development, and this energy is supplied by the food we eat. Nutrition science tells us about a balanced diet composed of carbohydrates, proteins, fats, vitamins, minerals, and water needed to maintain the normal functioning of our bodies.

Essential Food Ingredients in Human Nutrition

Carbohydrates are produced and stored in the form of sugar, starch, and fiber. There are simple and complex carbohydrates. Simple carbohydrates are broken down quickly by our cells via insulin and used immediately. Complex carbohydrates are broken down slowly, converted into simple sugars, and taken into our cells via insulin over time.

Simple carbohydrates provide quick energy and come from fruits, fruit juices, sugar-based snacks and drinks, white bread, white pasta, and baked goods. Complex carbohydrates provide sustained energy and come from whole grains (brown rice, whole-grain bread, barley), lentils, peas, beans, fruits, and vegetables.

Proteins are found in plants, whole grains, animal products, nuts, beans, and legumes. They are made up of subunits called amino acids. Our bodies can create many things with amino acids. Some amino acids can produce others if needed. They can also be recycled from retired proteins to make new ones. Half of the amino acids we use daily come from recycled proteins.

Fats (also known as lipids or fatty acids) are found in nuts, seeds, olives, animal products, and other sources. There are good fats and not-so-good fats. Fats are a major source of energy and play many roles in our bodies. In fact, 60% of our brain is made of fat! There are two essential fatty acids we need to consume through food, as our bodies can produce the others. These two essential fatty acids are Omega-3 and Omega-6.

In addition to the major food groups, our bodies need vitamins and minerals. Vitamins are essential nutrients required in small amounts and are found in plants (the colorful stuff), whole grains, and some animal products.

They help carbohydrates, proteins, and fats perform their functions. Of these, B vitamins are key components of our neural network. Others, like vitamin D, have been shown to be essential for optimal health, yet many people in society are deficient. Minerals must be consumed because our bodies cannot produce them.

They cannot be created or destroyed, and even if we burn food completely, minerals remain as ash. Plants, whole grains, and some animal products provide minerals. They work with carbohydrates to create energy, supply muscles with oxygen, and help repair injuries.

Last but not least is water, which is essential to life and found in plants, fruits, and animal products. Animal muscles contain more water than fats, and lean animal proteins contain a lot of water. The total volume of water in the body increases as the proportion of lean tissue increases.

Physically fit individuals tend to have more water and require more water than their sedentary counterparts. Water is a vital food component that helps maintain focus, motor control, body temperature, and fight off fatigue.

The U.S. Department of Agriculture's Recommendations for a Balanced Daily Diet

The U.S. Department of Agriculture (USDA) recommended the Food Pyramid as a guide to food composition. The Food Pyramid was created before the internet, and with the advancement of technology, it was replaced in 2011 by MyPlate, which provides a personalized approach to healthy eating based on individual dietary needs, preferences, cultural traditions, and budgets. MyPlate encourages people to enjoy their favorite recipes while incorporating healthier food choices.

It recommends that half of the plate be made up of fruits and vegetables, with the other half including whole grains, varying proteins, and low-fat or fat-free dairy milk or yogurt. According to MyPlate, the five food groups are Fruits, Vegetables, Grains, Protein Foods, and Dairy.

The 2015-2020 Dietary Guidelines for Americans emphasize the importance of an overall healthy eating pattern with all five groups as the building blocks, plus oils. While oils are not a food group, they are part of a healthy diet because they provide essential fatty acids and vitamin E.

Each food group includes a variety of foods that are similar in nutritional makeup, and each group plays an important role in an overall healthy eating pattern. Some groups are further divided into subgroups to highlight foods rich in certain vitamins and minerals.

For example, the Grains group encourages whole grains, which provide more fiber, magnesium, and zinc than refined grains. Protein foods are divided into seafood, meats, and nuts. While the Fruit and Dairy groups have no subgroups, Americans are encouraged to consume more whole fruits than juices, and more milk and yogurt than cheese. It is also recommended to reduce sodium, saturated fat, and added sugars.

As nutrition science has progressed, scientists have discovered vitamins, minerals, and other components that make up our foods. Food groups simplify dietary requirements by focusing on foods instead of nutrients.

Processed Foods and Why It’s Hard to Quit Them

Processed foods are any raw commodities altered from their natural state. They range from minimally processed to highly processed. Processed foods are typically altered during preparation through methods like freezing, canning, baking, or drying.

Common additives to avoid include hydrogenated vegetable oils, tropical oils (e.g., palm oil), preservatives like sodium nitrite or nitrate, flavor enhancers like monosodium glutamate (MSG), and added sweeteners like corn syrup, cane juice, or artificial sweeteners. Generally, the shorter the ingredient list in processed foods, the better.

Eliminating unhealthy processed foods can help with weight loss and lead to a healthier lifestyle.

Why It’s Hard to Switch from Processed to Natural Foods

Powerful advertising and addiction to processed foods are major factors. Salt and sugar often keep consumers coming back. Additionally, healthier foods tend to be more expensive, making fresh food harder to obtain. As a result, people turn to processed foods, which are cheaper and more accessible. One alternative is to buy frozen or canned foods in bulk without additives.

Ultra-Processed Foods

The term "ultra-processed foods" comes from the NOVA food classification system, developed by researchers at the University of São Paulo, Brazil. This system classifies food into four categories based on the degree of processing:

1. Unprocessed or minimally processed foods, such as fruits, vegetables, milk, fish, pulses, eggs, nuts, and seeds, with no added ingredients.
2. Processed ingredients, such as salt, sugar, and oils, which are added to other foods.
3. Processed foods, made by combining foods from groups 1 and 2. Examples include jam, pickles, tinned fruits and vegetables, homemade bread, and cheese.
4. Ultra-processed foods, which contain ingredients not typically found in home kitchens, such as preservatives, emulsifiers, sweeteners, and artificial colors and flavors. These foods often have a long shelf life.

Why Ultra-Processed Foods Are Bad

Ultra-processed foods often contain high levels of saturated fat, salt, and sugar, and they leave less room in our diets for nutritious foods. These foods tend to be low in fiber, high in sugar, and calorie-dense. Some studies suggest that additives in ultra-processed foods could have negative health effects. Longitudinal studies in the Americas and Europe have linked ultra-processed food consumption to obesity, high blood pressure, type 2 diabetes, and even dementia. Other research, including studies published in **The BMJ**, has linked ultra-processed foods to early death.

Not All Ultra-Processed Foods Are Bad

Recent research shows that not all ultra-processed foods are harmful. For instance, mass-produced whole grain bread is considered healthy. A study using 30 years of data evaluated the relationship between ultra-processed food consumption and long-term health. It found that those who ate a high-quality diet (rich in fruits, vegetables, whole grains, and healthy fats, and low in sugary drinks, salt, and processed meats) showed no clear association between ultra-processed food consumption and premature death.

Should Dietary Guidelines Advise Against Ultra-Processed Foods?

National dietary guidelines already advise people to limit highly processed foods that are high in refined grains, saturated fats, sugar, and salt. Recommending a reduction in all ultra-processed foods could disproportionately affect low-income individuals, as many ultra-processed foods, such as supermarket bread, are affordable and convenient.

Bread is also a key source of fiber in many diets. While unhealthy diets and obesity contribute to poor health, we should focus on improving population diets without causing harm through excessive restrictions on affordable foods.