What occurs when a person eats in excess?

By Erica Kannall Updated December 12, 2018

Table of Contents Show

Energy in – eating too many kilojoules
Energy in – eating too few kilojoules
Energy out – exercise to burn kilojoules
Making practical changes to your energy balance
Where to get help

If you eat excess calories, your body stores the energy as glycogen or fat to use at a later time. These compounds get stored in your liver, muscles and fat cells. Over time, continually eating excess calories causes your body fat stores to expand, resulting in weight gain. You'll have to create a calorie deficit to lose the excess calories your body has stored.

Consuming excess calories means you're eating more than your body burns off in a day. Some energy expenditure comes from body processes, such as your heart beating, breathing and digestion. The remainder of the energy you expend daily is due to physical activities, such as walking, cleaning the house, climbing stairs, biking or gardening. If you eat more than you burn in a day, your body stores the excess calories to use later when calories are scarce.

Some excess calories you consume from carbohydrates are converted to and stored as glycogen, a complex carbohydrate, in your body. Your body stores glycogen primarily in your muscle and liver cells. Every 1 gram of carbohydrate gets stored along with 3 grams of water. According to Iowa State University, a healthy adult body can store about 500 grams of carbohydrate. Skeletal muscles store about 400 grams or glycogen, the liver stores 90 to 110 grams of glycogen and your blood circulates roughly 25 grams as glucose. This means your body is capable of storing about 2,000 calories of carbohydrates.

Once your glycogen stores are full, your body stores excess calories from carbohydrate as fat. Excess calories from fat and protein intake get stored as fat in the body as well. Adipose cells, or fat cells, store the extra calories in the form of triglycerides, a type of fatty acid. Most of these fat cells are found between your skin and muscle while others surround your organs, according to the University of Rochester Medical Center. Everyone has a different number of fat cells, but it's the size of the cells that matters more.

Eating an excess of 3,500 calories contributes to a weight gain of roughly 1 pound of body weight, according to MayoClinic.com. As you eat excess calories, the fat accumulates inside your adipose cells causing the cells to expand and increase in size. After enough fat cells enlarge in an area, you begin to look fat. In order to reduce the fat stored in cells and lose weight, you must create a calorie deficit by reducing food intake or increasing exercise. While few people want to have excess body fat, some fat storage is essential to allow your body to have energy reserves, protect internal organs, insulate the body and protect nerves.

If we regularly eat more kilojoules than our body needs, the excess will be stored as body fat.
Achieving or maintaining a healthy weight is all about balancing energy we take in and energy we burn.
A single energy-dense meal may contain most of an adult’s daily kilojoule intake and drinks can be high in kilojoules too. So, when eating out, look for kilojoule labelling on menus and check before you choose.

Achieving or maintaining a healthy weight is all about balancing the energy we take in with the energy we burn (energy out).

Tips for watching the energy you take in:

enjoy a variety of foods from each of the five food groups in the amounts recommended
watch your portion sizes – particularly foods and drinks that are high in kilojoules
limit your intake of energy-dense or high-kilojoule foods and drinks (check the kilojoules on the menu when eating out)
if you do have an energy-dense meal, choose food or drinks that have fewer kilojoules at other meals in the day.

Tips for watching the energy you burn:

be active in as many ways as you can throughout the day – take the stairs instead of the lift, get off the bus a stop early and walk, break up sitting time at work
exercise regularly – at least 30 minutes of moderately intense activity on most days
do more activity when you eat more kilojoules.

Achieving and maintaining a healthy weight is good for your overall vitality and well-being and helps prevent many diseases.

Energy in – eating too many kilojoules

When we regularly eat more kilojoules than our body needs, the spare energy is stored as fat.

Eating as little as 100kJ extra each day (or burning 100kJ less by exercise), can lead to one kilogram of body fat creeping on over a single year.

If you are above your healthy weight, to lose one kilogram (kg) of body fat in two months (without increasing your physical activity), you would need to eat around 600kJ less per day.

Energy in – eating too few kilojoules

When we regularly eat fewer kilojoules than our body needs our weight may decrease.

If you experience weight loss that puts you outside of your healthy weight range or is unintentional, it is important to seek advice from your GP or Dietitian.

Energy out – exercise to burn kilojoules

When you are active, your body burns more energy (kilojoules). Exercise not only uses up stored energy, but also helps to stimulate muscle development. The more muscle tissue you have, the more kilojoules you can burn. Regular physical activity helps you manage your weight and maintain good health – it can even reduce your risk of chronic diseases.

To actively lose weight, aim to do 60 – 90 minutes moderate-intensity physical activity most days of the week. Start small and gradually work your way up. Remember, weight you lose gradually is more likely to stay off than weight you lose through crash diets.

If you are over 40, have a pre-existing medical condition or you haven’t exercised for some time, see your doctor before starting a new fitness program.

Find out more about physical activity

Making practical changes to your energy balance

Reducing the amount of kilojoules we eat and drink every day, or doing more exercise every day, even by small amounts, can all add up and make a difference.

This could be as easy as:

having salad or rice as a side instead of hot chips
ordering grilled instead of deep-fried or crumbed options
swapping full fat for low fat or skim milk
swapping a high sugar drink for water
swapping a fried food for a low kJ one
swapping a large food or drink serve for a smaller one
avoiding meal deal or ‘two for one’ promotions
checking the kilojoules on menus and choosing the lower kilojoule option
having fewer kilojoules at other meals
doing more activity when you eat more kilojoules.

Where to get help

Balancing energy in and out, Nutrition Australia. More information here.

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