2.3 Describe factors influencing energy requirements of older people

This guide will help you answer 2.3 Describe factors influencing energy requirements of older people.

Energy requirements change as people get older. Age, health status, lifestyle, and body composition all affect the amount of energy someone needs. Getting the balance right helps older people stay healthy and active.

In this guide, we will cover the factors influencing energy needs in older people. Each factor shapes how much food energy is required for day-to-day living and overall wellbeing.

What Are Energy Requirements?

Energy requirements mean the amount of food energy, measured in kilocalories (kcal), a person needs. This keeps the body running: breathing, digesting, moving, and thinking. The body’s metabolism—how fast it uses energy—varies with age, health, and activity.

Energy needs are not the same for everyone. They depend on many different things. For older people, both physical and biological factors influence these needs.

Age-Related Changes

Energy needs for most people decline with age. This happens mostly because of changes in the body and daily habits.

• As people age, they often lose muscle and gain fat. Muscle uses more energy than fat, so less muscle means less energy burned.
• Most older people move less than younger adults. Less movement uses less energy.
• Some older adults have health conditions or take medicines that lower their appetite or slow their digestion.

These age-related changes mean that an older person usually needs fewer calories than when they were younger, but still needs the same amount of vitamins, minerals, and protein to stay healthy.

Body Composition

Body composition describes the amounts of muscle, fat, bone, and water in the body.

• People usually lose muscle as they get older (sarcopenia). This lowers the basal metabolic rate (BMR)—the baseline amount of energy burn at rest.
• Some older people gain fat, which stores energy but uses less.
• A heavier but muscular person may need more energy than a lighter person with less muscle.

If an older person loses a lot of weight or muscle, they might feel weak or tired more easily. This makes it harder to do things, leading to less activity and further muscle loss—a cycle that affects energy needs.

Physical Activity Levels

Physical activity has a big effect on energy requirements.

• Active older people need more energy than those who sit most of the day.
• Walking, gardening, housework, and hobbies can raise energy needs.
• Those who are bed-bound or spend much time sitting will need less food energy than someone who still walks daily.

Many older people reduce activity as they age. Illness, pain, or lack of confidence can all play a part. So energy needs may fall, but the need for nutrients stays high.

Medical Conditions

Health problems are more common in older adults. Some make a person burn more or less energy.

• Illnesses that cause fever, infections, or recovery from surgery will raise energy needs since the body works harder to heal.
• Some diseases, like cancer or lung conditions, can also increase energy used at rest.
• On the other hand, conditions like heart failure may reduce the energy someone can use, making them move less.
• Conditions that affect the gut (like Crohn’s disease) may affect how much energy is absorbed from food.

Long-term illness may lower appetite or change how food is digested, making it tricky to match food intake to needs.

Medication

Some medicines influence energy requirements or appetite.

• Steroids can lead to weight gain, affecting body composition and energy use.
• Some medicines for mental health may make people feel more hungry.
• Other medicines may lower appetite or cause side effects like nausea, reducing food intake and energy use.

It is important to consider medication when assessing energy needs.

Gender

Men and women have different energy requirements at any age, including older age.

• Men usually have more muscle mass than women. They burn more energy at rest and when active.
• Women often have more fat as a proportion of body weight, which uses less energy.

So, a healthy older man may need more energy than a woman of the same age and weight.

Weight

Body weight affects energy requirements.

• A heavier person burns more energy because more mass must be moved and supported.
• If someone carries more weight because of fat, their extra needs aren’t large, since fat uses less energy than muscle.
• Very thin or underweight people have lower energy needs but need nutrient-dense food to avoid malnutrition.

Rapid weight loss or weight gain in older adults can be harmful and should be checked by a health professional.

Basal Metabolic Rate (BMR)

BMR is the amount of energy burnt at complete rest.

• BMR falls with age as muscle is lost and replaced with fat.
• Some medical conditions can increase or decrease BMR.

Most of an adult’s energy use comes from BMR, but it becomes even more important in older people who are less active.

Thermic Effect of Food

This is how much energy the body needs to digest and use the food eaten.

• The thermic effect is usually around 10% of daily energy needs.
• If a person eats less or digests food poorly, this effect falls.

This is a small factor, but it matters more in those with slow digestion or eating lower amounts.

Social Factors

Social life affects eating and activity, and this changes with age.

• Some older people live alone, which can make cooking and eating balanced meals harder.
• Loss of a spouse, friends, or family can lead to low mood and less interest in food.
• Lack of transport, money for food, or help with shopping also limit energy intake.

A reduced social life can mean falling energy requirements and less enjoyment of food.

Psychological Factors

Mental health impacts energy needs and intake.

• Depression is common in older people and often leads to low appetite and eating less.
• Stress, anxiety, or confusion (like dementia) can change eating habits.
• Low mood may lower activity levels, which reduces energy use.

Mental health can be just as important as physical health in affecting energy needs. Support with eating and social contact can help.

Sensory Changes

Senses of taste, smell, and vision often weaken with age.

• Food may taste bland, making older people eat less.
• Poor vision or difficulty handling cooking tools can make meal preparation harder.
• Poor dentition (bad teeth or bad fitting dentures) can limit what can be eaten, such as tough meats or raw vegetables.

These changes might cause someone to eat less or make poor food choices. Less food leads to lower energy intake and reduced energy requirements.

Digestive Changes

Digestive ability can fall with age.

• Some older people produce less stomach acid, which affects how nutrients are absorbed.
• Problems chewing or swallowing can reduce food intake.
• Slower movement of the gut can cause feelings of fullness or constipation, making people eat less.

Digestive issues may reduce both energy intake and needs.

Illness Recovery

After an illness or operation, energy requirements often rise.

• Healing burns more energy than normal.
• This extra need lasts days or weeks while the body repairs itself.

If intake is too low during recovery, older people can become weaker or lose more muscle, making recovery slower.

Climate and Living Conditions

Where someone lives can affect how much energy they need.

• Those living in cold houses may need more energy to stay warm.
• In hotter climates, energy needs may fall because the body works less hard to keep warm.

Poverty or poor housing conditions can make keeping warm or getting healthy food harder, lowering both intake and energy requirements.

Cultural and Personal Preferences

Food choices and meal patterns are shaped by culture and personal taste, which can affect how much energy is taken in.

• Some cultures eat more small meals, others prefer one main meal a day.
• Cultural beliefs may limit certain food types, affecting energy and nutrient intake.
• Personal dislikes or suspicion of unfamiliar foods may make getting enough energy harder.

Preferences can lead to good eating habits or restrict intake below needs.

Impact of Smoking and Alcohol

Smoking and alcohol both influence appetite, metabolism, and energy use.

• Long-term smoking can blunt taste and smell, lowering appetite.
• Alcohol has calories, but drinking too much can cause poor diet, reducing nutrient intake.

Not everyone smokes or drinks, but these factors can affect how much energy someone needs and gets.

Nutritional Knowledge and Support

Awareness of healthy eating affects energy intake.

• Some people may not know which foods give enough energy and important nutrients.
• Lack of access to advice or bad past experiences can shape food choices and the amount eaten.

Community groups and health professionals can help raise knowledge of the right balance for older people.

Use of Supplements

Supplements don’t add to energy intake unless they have calories. Some might take supplements instead of food, which may lower energy intake.

Supplements with high calories, like nutritional drinks, can be useful for those who struggle to eat enough due to illness or weakness.

Risk of Malnutrition

Older people who do not get enough food energy are at higher risk of malnutrition. Signs include:

• Unintentional weight loss
• Muscle weakness
• Tiredness
• Slow healing

Eating more nutrient-rich, calorie-dense foods or using supplements can help those at risk.

Disability and Mobility Issues

Limited ability to move can reduce activity levels.

• Wheelchair users or bed-bound people use less energy compared to active peers.
• Those with pain or balance difficulties will walk less, lowering need for calories.

Energy needs must be balanced carefully in those with mobility issues to avoid further loss of stamina or unwanted weight gain.

Appetite

Appetite often changes with age.

• Some lose interest in food or feel full quickly.
• Tiredness, illness, or medication can make it harder to feel hungry.

Lower appetite reduces calorie intake, which in turn lowers body energy use if less activity is done.

Final Thoughts

Energy requirements in older people are shaped by many factors—biological, social, psychological, and environmental. Each factor can increase or lower how much food energy is needed to maintain health.

Maintaining a good balance between energy intake and needs is key. Losing too much weight, muscle, or energy can reduce the quality of life and independence. Health conditions, social isolation, and poverty may all raise the risk of eating less than is needed.

Regular reviews of diet, activity, and health are helpful. Older people should have access to supportive environments, affordable food, and good information. Family members, carers, and professionals can play a crucial role in helping older people to eat and live well.

In summary, understanding what shapes energy requirements—and making simple adjustments—can support older people to stay healthy, enjoy mealtimes, and continue living well as they age. Focusing on the unique needs of each person helps ensure energy needs are met, reducing the risk of ill health and promoting wellbeing.