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Portion size: how much should I be eating?

Updated: May 9, 2022

Portion and Serving sizes

Understanding the science of food and how it works or does not work is important, but something also very important is the understanding of the food portions and servings. That is how much of a particular food is ideal for a normal person to eat at a go in a meal.

What are portion and serving sizes?

A portion is how much food you deliberately decide to eat at a time. Either the food you made in your kitchen, or the ones bought in a restaurant, or in a packed form. You can always decide your portion.

Serving size is fondly the amount of food recommended per meal listed in the nutritional facts of a food label. Hence, the nutritional values written on the food label are for the serving size that the manufacturer has advised.

Most foods bought or even made at home contain more than one ideal serving.

You mostly see per 100g serving, 200g serving and so on.

Different foods have different serving sizes. This is primarily because they are not of the same composition or weight. These weights and compositions of foods are what determine the nutritional contents of the food according to their quantity. That is the protein, carbohydrates, fats, vitamins and minerals, iron, phosphorus, potassium, calcium, etc. vary in the food, based on the quantity served.

Although, our focus here is on portion and serving sizes, so we will be talking more about that.

Portion or serving sizes have been carefully determined based on the nutritional needs of humans in a normal healthy condition. That is for a person without any disease.

credit: Bupa

Also, it is expedient to know that the portions can also vary or be different for individuals with varying lifestyles. For example, the average food serving for a sedentary person will be different for a person that is of high activity level because of the amounts of energy they both use up in carrying out their daily chores are not the same.

The serving sizes vary from food class to food class. In other words, the standard portion or serving size of carbohydrates is different from that of fats. Likewise, the standard serving size for proteins is also not the same as the standard serving size for vitamins or minerals. And so it is for all food classes and food groups.

The essence of understanding and carefully following the standard food portions or servings is for us to have adequate required food nutrients and live healthy with minimal health complications and diseases.

It is important to be aware of portion sizes, as too much or too little of any type of food can increase our risk of health problems. Knowing that no food class or group is bad for health except in disease conditions where dietitians recommend what to eat or not.

All food classes are for our consumption, and in moderation.

This is because the body may be getting too much or too little of what it needs to stay healthy.

Now let us take a look at the nutrients and how much an ideal serving size is.


Carbohydrates are the chief energy source in the body. They provide the body with fuel for producing energy to work daily. The body could also use other food classes for energy production, but carbs are the default and natural source of fuel for the body.

That is why they are important in the diet. Carbohydrates are found in all plant based products and some the animal based too.

Examples of carbohydrates sources are all plant produces like cereals and grains (wheat, rice, oats, sorghum, quinoa, corn, etc) roots and tubers (potatoes, yam, cocoyam), vegetables and fruits, nuts and drupes etc.

This also includes all their derivatives after slight or heavy processing.

What is a carbohydrate serving?

The following items are equivalent to serving size.

1- 1 ½ medium slices of bread

Pasta (boiled) 2-3 tablespoons

Rice (boiled) 2-3 tablespoons

2 egg sized potatoes (boiled)

1 medium baked potato (with skin)

Breakfast cereal: 4 tablespoons

Porridge oats: 4 tablespoons

TOP TIP: Choose whole grains or higher fibre versions with little or no added sugar, salt and fat.

5-6 servings per day are recommended.


Proteins are known for their essential body tissue building functions. They are foods enriched with nutrients that helps with rejuvenating the body and repairing tissues and organs. They are essential and unique for growth and development as well as organ maintenance, especially for growing children and aged adults.

Proteins are found in a variety of foods both plant based and animal based. Animal based protein in recent times have been linked to the unfriendly increase in lifestyle diseases like heart diseases, alzheimers disease, hypertension, stroke, metabolic disorders, etc among many adults.

Examples of foods rich in proteins are legumes and pulses (beans, chickpeas, kidney beans, etc), meats, seafood, nuts and seeds (peanuts, sesame seeds), some cereals (quinoa, oats), blue green algae (Spirulina), egg, dairy products

What makes a serving of protein?

Fats and oil

Fats and oils are also important food class that helps the body to execute certain functions and transport key nutrients the body. Fats and oils are not all dangerous to health, and neither should they be totally avoided. Fats and oils are to be eaten or added to meals in small amounts, but yet very vital for the body’s overall function.

Fats are in the solid state, while oils are in the liquid state, both at room temperatures. Healthy fats with minimum cholesterol levels and high omega 3 and omega 6 levels are recommended.

Fats are present in plants and animals likewise.

Popularly used oils include olive oil, sunflower oil, sesame oil, coconut oil, etc.

Examples of foods having some good fats are whole grains (quinoa, oats,), avocado, seafood, nuts and seeds (almonds, cashew nuts, groundnuts, sesame seeds, melon seeds, etc), etc.

What makes a serving of fat and oil?

Type of oil/spread and its Amount in grams (g)

1 teaspoon of butter or spread 5g

1 teaspoon of oil 3g

3 servings daily of unsaturated fats is recommended daily dietary allowance.

Vitamins and Minerals

These are food nutrients required by the body in small amounts but yet very essential for the body’s healthy state.

Not all vitamins and minerals can be made by the body itself, so they need to be taken in through our diets in some good amounts.

A deficiency in a vitamin or mineral could lead to serious disease conditions. That is why they are recommended to be eaten daily.

The major possessors of these classes of food are vegetables and fruits.

All vegetables and foods and their derivatives as well as other plant based foods have great amounts of vitamins and minerals required by the human body.

What makes a serving for fruits and vegetables?


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