Balanced diet: definition
A Healthy and Balanced Diet
Essential Nutrient Groups
The energy in our food comes from three macro-nutrients:
Besides these macro-nutrients, our bodies also need vitamins, minerals and water.
What is a Balanced Diet?
A balanced diet consists on consuming all of these nutrients in the correct amounts.
But what are the correct amounts of nutrients?
The US government's health specialists (through the US Department of Agriculture or USDA) have established healthy eating guidelines that tell us the proportions that we should eat of each of these nutrients.
And to make things easier, they have grouped foods into categories based on their similarities and properties, these are known as "Food Groups".
These healthy eating guidelines define how much of each food group people need to eat in order to live healthy lives.
But before going into each food group, let's explain what these micro-nutrients are, and why are they so important for our health:
Micro-nutrients in Food
The energy contained in these macro-nutrients is high, and our body uses them not only as a source of energy, but also as the chemical building blocks for its internal structure, our tissues, bones and cells are built from what we eat and powered by it too:
Nutrient (1 g)
As you can see fat is packed with calories, more than duplicating the calories in the same amount of carbs or protein.
There are thousands of proteins, and the protein in our food is broken down by our body into their component molecules, called amino acids.
Our body then reassembles the amino acids into new proteins. It does so joining them up in sequences set down by our DNA.
There are some 20 different types of amino acids, and eight of them are essential in our diet (our bodies can make the others from the eight essential amino acids).
It is important (especially for those following vegan or vegetarian diets) to eat a mix of plant protein to make sure that they incorporate these essential amino acids in the correct amounts in their diets.
Fats and Oils
Fats and oils share a similar chemical structure. The obvious difference is that oils are liquid (i.e. olive oil, canola oil) at room temperature and fats are solid or semi-solid at room temperature (lard, butter).
The fats in our diet are known as triglycerides, meaning that they have a "head" formed by a molecule of glycerol, a sweet tasting type of alcohol, and three fatty acid tails linked to the head. (that is why they are "tri" glycerides, "tri" = three).
These tails are what make a fat liquid or solid:
These fats have "straight" tails because the chemical bonds between the carbon atoms that make up the fatty acid chain are linked with "single" bonds to each other. Being straight, they can line up and pack closely together, the attraction between close chains enhances this effect. The outcome is a solid fat.
Most animal fats are saturated fats.
These fatty acids have "bent" tails due to the double bonds between some carbon atoms along the chain. This does not allow them to pack neatly together so they are liquid.
Depending on the quantity of double bonds they can be mono-unsaturated (only one double bond), or poly-unsaturated (several double bonds).
Most vegetable fats are unsaturated.
Carbohydrates are chemical compounds that include different types of sugars, starch and cellulose. The carbohydrates in our diet come from plants.
Glucose, is a simple sugar and is the building block of both cellulose and starches. Glucose molecules link to each other forming long "polysaccharide" (from "poly" = many and " saccharide" = sugar) chains. When these are very long and pack closely together as crosslinking chains, they are known as Cellulose.
Cellulose makes up the bodies of plants and humans can't digest it (the crosslinking is hard to break apart). This type of carbohydrate is known as fiber.
As we can't digest it, we can't get energy from fiber but it is good for your digestive system. It comes in two varieties:
Insoluble Fiber. Mostly made up of cellulose, you can find it in wheat bran, whole grains and vegetables.
Soluble Fiber dissolves in water and forms a viscous gel which has cholesterol lowering properties. It is found in oat bran, nuts, lentils, peas and beans.
There is evidence that fiber helps to control weight, reduce irritable bowel syndrome (IBS) symptoms and have positive effects on heart disease, diabetes and constipation.
The plants store the enegy that they obtain from photosynthesis as starch, which are shorter polysaccharides that we can easily digest.
Cereals produce seeds which we call grains and these are the main sources of starch: rice, wheat, corn, rye, oats. Tubers are also rich in starches.
Starches are the main components of bread, pasta, biscuits.
Plants build simple sugars by combining Hydrogen, Oxygen and Carbon atoms. These can have five or six carbon atoms linked together to form monosaccharides such as glucose, fructose (found in fruits), galactose (found in milk). These can also link up to form di-saccharides (two sugar molecules) such as sucrose (what we know as "sugar"), lactose (in milk), and maltose, just to mention a few.
Sugar is very energy dense (lots of calories packed into small quantities).
A Healthy Diet
Fat, carbohydrates and protein have to be eaten in the proper proportion to help you maintain a healthy body weight and feel energetic and vital. To simplify the process of including them in your diet, the concept of Food Groups was created:
Food groups are categories that combine different foods that are similar in composition and nutrients, so that they can be easily understood and applied to a diet plan.
The US has defined five main food groups:
Your diet should include foods from these five groups.
And should limit the intake from these other "groups" because they are packed with calories and may also have negative health effects:
Fruits are a good source of fiber (especially their skins), vitamins and minerals. They also provide water to attain your daily hydration goals. They are rich in sugars and that is why your balance of vegetables and fruits should include more veggies than fruit.
Despite the MyPlate recommendations ( 2 ), fruit juice is not the same as "natural" fruit. It often lacks the fiber and concentrates the sugars. In the case of processed juices, they may even have added sugar.
Health Benefits of Vegetables and Fruit
Heiner Boeing, et al., (2012) ( 1 ) performed a meta-analysis of different scientific studies and found that there is evidence that an increase in the consumption of vegetables and fruits has the following positive health effects:
- Hypertension, coronary heart disease and stroke are improved
- "Probable evidence" that the risk of cancer drops
- It may prevent body weight gain.
- Indirectly reduces the incidence of type 2 diabetes mellitus.
- "Possible evidence" that it lowers the risk of certain eye diseases, dementia and the risk of osteoporosis.
- Prevents asthma, rheumatoid arthritis and chronic obstructive pulmonary disease
Group - age
Cups per day
Women 19 - 30
Other countries recommend that you should aim at 2 servings of fruit each day.
A serving is a 3 ounce (80 g) portion of fruit: a slice of cantaloupe or melon, one banana, an apple, a pear.
Include a variety of fruit in your diet: berries, pineapple, figs, kiwi, apricots, peaches, mangoes, oranges, grapefruits. There are many options.
The USDA recommends the following daily intake of vegetables:
Group - age
Cups per day
Women 19 - 50
Men 19 - 50
In other parts of the world, the target is set at 5 servings of vegetables and fruits per day, both should add up to roughly one third of your daily food intake.
Americans don't eat enough vegetables (mostly potatoes and most of them as French fries!). Potatoes are starchy vegetables, full of carbohydrates, try to replace them with other veggies.
You can include more vegetables by eating a salad as a side dish during lunch or dinner.
Include colored vegetables such as tomato, bell peppers, squash and add a side salad to your lunch. Add leafy vegetables such as kale, spinach, celery and arugula too.
Starchy vegetables include sweet potato, potatoes, green peas. Beans and legumes (soybeans, tofu, black beans, chickpeas, lima beans) can also be considered as part of the protein foods group because they have a large proportion of protein too.
Foods maide from cereals (wheat, barley, rice, corn, oats, rye) are considered grains, these are "starchy foods", rich in carbohydrates.
You will find grains in pasta, bread, tortillas, popcorn, your breakfast cereal, and processed foods made with flour and starches. Quinoa, bulgur and buckwheat can also be considered grains.
The best option is to eat "whole" grains (whole wheat, whole oats) because they contain a higher proportion of fiber and also more minerals and vitamins -which are more concentrated in the fiber rich husk that is not removed from whole grains.
Brown rice, whole wheat pasta are options of whole grain based foods.
Half your grains should be whole grains.
Baked grain products (bread, biscuits, cookies) can have plenty of fat (trans fats or saturated fats) try to chose low fat options but bear in mind that low-fat processed foods usually compensate the lack of fat by adding sugars to the product. So check the nutrition facts label.
Starchy vegetables such as potatoes fall in this category, as they are rich in simple carbs. The potatoes' skins is a good source of fiber.
The USDA recommends the following daily intake of grains (in ounce equivalents):
Group - age
Women 19 - 50
Men 19 - 30
Men 31 - 50
One slice of bread, 1 cup of breakfast cereal, half a cup of cooked rice or pasta are equal to one ounce equivalent.
Some Health Benefits of Whole Grains
Skerret and Willett (2010) ( 3 ) point out that carbohydrates have grown in the American diet at the expense of fat and most of it is highly processed grains, from which the healthy fiber, vitamins, minerals, phytonutrients and some healthy plant fats have been removed.
They state that these highly processed grains are linked "an increase in triglycerides and a reduction in protective HDL" (HDL is the "good cholesterol").
On the other hand, "eating whole grains or cereals high in fiber, rather than highly refined grains, reduces the risk of cardiovascular disease and type 2 diabetes. Although reductions in the risk of colon cancer by diets rich in whole-grain fiber have been difficult to document, such a dietary pattern has been clearly associated with reductions in constipation and diverticular disease."
Eggs, fish, beans, seafood, meat, poultry, nuts and seeds are all sources of protein.
Aim for 2 portions of fish each week, one of them an oily fish. The USDA recommendation is 8 ounces of cooked seafood per week.
Fish is a good choice because not only does it have vitamins and minerals, oily fish ar rich in healthy omega-3 fatty acids. Canned, frozen, fresh fish are all valid options. Small fish such as sardines or trout will have lower levels of toxic mercury in them in comparison to large fish such as tuna.
A great option for vegetarians (ovo-lacto vegetarians), they have plenty of protein (in the white of the egg).
Poultry, pork, mutton and beef are excellent sources of protein plus iron, zinc and B vitamins. Aim at lean cuts and avoid the skin of poultry. Cut off excess fat (meat has mainly saturated fat).
Cook well to kill any bacteria lurking in the uncooked parts.
Aim at high quality proteins sources avoiding processed meats such as sausages, hot dogs, bacon, and cold cuts such as ham.
Vegetable proteins are beneficial
Beans, legumes, chickpeas and foods obtained from them (tofu) are sources of vegetable proteins. Nuts, seeds also have protein. Consume a variety of different foods.
They also have a positive effect when compared to animal protein: Skerret and Willett (2010) (3) cite the "Nurses' Health Study", which suggests that "eating more protein from beans, nuts, seeds, and the like, while cutting back on easily digested carbohydrates reduces the risk of heart disease... eating more animal protein while cutting back on carbohydrates did not reduce heart disease risk".
This suggests that saturated fats associated to animal origin protein may be a negative influence for those proteins.
The USDA recommends the following daily intake of protein sources (in ounce equivalents):
Group - age
Women 19 - 30
Men 19 - 30
Men 31 - 50
Adults usually don't consume enough dairy products. The best choice are fat-free or low-fat options (once again keep an eye on the added sugar content).
Cheese, milk and youghurt are not only good sources of protein, they are rich in calcium -which is good for your bone health.
Lactose intolerant people can try lactose reduced milk or non dairy alternatives such as almond milk or soybean milk.
The daily dairy allowance recommended by the USDA is:
Group - age
Despite being calorie dense products which should be consumed in small amounts, they are essential for heart health and brain function.
Try to avoid trans fats and fried foods (they soak up the oil they are fried in).
Extra virgin olive oil, oils from nuts, olives and seeds, avocados and fish oils provide healthy fat options, and they are also a source of vitamin E. Peanut butter is roughly 50% fat, and combines saturated palmitic oil with unsaturated oils.
Unsaturated fats are an important part of a healthy diet they come in two main types: monounsaturated fats (such as canola and olive oil or almonds, cashews and avocados), and polyunsaturated fats like the oily fish's omega-3 fats or omega-6 fats (in safflower or soybean oil and Brazil nuts).
Some examples of oil content in foods: you will find one tablespoon of oil in:
- One-half medium avocado
- 24 large olives
- One-half tablespoon of peanut
- 10 half walnuts
The USDA's daily allowance of oils is the following:
Group - age
Women 19 - 30
Men 19 - 30
This covers the food groups, but there are two additional categories which include food which should be consumed sparingly:
As mentioned further up (see Fats), solid fats are mostly saturated fats, whose physical and chemical structure cause them to be solid at room temperature.
Some oils, such as palm oil, coconut oil and palm kernel oil are high in saturated fats and considered as fats not oils by the USDA's guidelines.
Other examples of solid fats are animal-origin fats: beef fat, tallow, pork fat, chicken fat, shortening and butter.
Finally are the artificial "Trans Fats":
These are man made fats produced by saturating vegetable oils: the double bonds of healthy oils are replaced with hydrogen atoms, a process known as "hydrogenation".
This is a high pressure process catalized with nickel or palladium metals. Trans fats are not good for the cardiovascular system.
Trans fats are used in processed foods because they provide texture to foods. They are bad for cardiovascular health (3).
Some natural trans fats are produced by bacteria in the gut of cows and sheep. These are harmless and "this trans fat may impart health benefits beyond those associated with CLA" (Field et al., 2009) ( 4 )
Skerret and Willett (2010) (3) found that "a low intake of trans and saturated fat and a higher intake of unsaturated fats reduce the risk of cardiovascular disease and diabetes".
Sugar is usually added to processed foods to make it more palatable, low-fat foods tend to have plenty of added sugar to compensate the lack of flavor that fat removal causes.
Americans tend to eat too many sweet sugary processed foods.
Candy, chocolate, cakes, biscuits, sodas and cola drinks, ice cream... all of these pack a lot of calories and may lead to weight gain and an increase of health risk conditions such as heart disease or type 2 diabetes. But evidence is contradictory for the time being (Khan and Sievenpiper, 2016)( 5 ).
Check the ingredients list of the processed food you buy, sugar will appear there under a wide variety of names:
- Brown sugar
- Corn syrup
- High-fructose corn syrup
- Raw sugar
Those are just a few of the names "sugar" adopts when it is added to food.
Remember that eating a wide variety of healthy foods will promote good health and protect you against chronic disease.
A well balanced diet means eating different foods from each of the five food groups in the recommended proportions.
Avoid trans fats, saturated fats, excess sugar and salty processed foods. Eat a variety of foods from each group.
The USDA's MyPlate initiative (2) does not mention water intake, salt restriction or increased physical activity as other factors to take into account in improving health. But they too should be taken into account for a balanced and healthy lifestyle.
Cite this article:
A. Whittall. ©2018. Balanced Diet. Patagonia Wellness, 14 Oct. 2018. http://www.patagoniawellness.com/diet-food/balanced-diet.html
Subject: Balanced Diet: eat a variety of foods from each food group in the recommended proportions.
References and Further Reading
(1) Heiner Boeing, et al., (2012).Critical review: vegetables and fruit in the prevention of chronic diseases. Eur J Nutr. 2012 Sep; 51(6): 637-663. 2012 Jun 9. doi: 10.1007/s00394-012-0380-y
(2) USDA MyPlate.
(3) Patrick J. Skerrett, and Walter C. Willett, (2010). Essentials of Healthy Eating: A Guide. J Midwifery Womens Health. 2010 Nov-Dec; 55(6): 492-501. doi: 10.1016/j.jmwh.2010.06.019
(4) Field CJ, Blewett HH, Proctor S, Vine D., (2009). Human health benefits of vaccenic acid. Appl Physiol Nutr Metab. 2009 Oct;34(5):979-91. doi: 10.1139/H09-079
(5) Khan TA, Sievenpiper JL. (2016). Controversies about sugars: results from systematic reviews and meta-analyses on obesity, cardiometabolic disease and diabetes. Eur J Nutr. 2016 Nov; 55 (Suppl 2): 25-43. doi: 10.1007/s00394-016-1345-3. Epub 2016 Nov 30
Nutrition Australia Healthy Eating Pyramid.
National Health Service, UK, Eating a balanced diet. Page last reviewed: 16/03/2016
NIH, National Heart, Lung, and Blood Institute (NHLBI) USA Healthy Eating Plan.
Department of Health & Human Services, State Government of Victoria, Australia. Food variety and a healthy diet.