Energy balance Grain Chain 2016

Energy balance Grain Chain 2016

Energy essential for life A regular supply of dietary energy is essential for life, and is required to fuel many different body processes. These include keeping the heart beating and organs functioning, maintenance of body temperature, muscle contraction and growth. Daily energy requirements vary widely from one individual to the next. This is due to factors such as sex, body size, bodyweight, climate and physical activity levels.

Energy intake Energy is provided by macronutrients (carbohydrate, protein, fat) in the food and drink we consume. The amount of energy that each of these macronutrients provides varies: Fat is the most energy dense nutrient, and provides 9kcal (37kJ)/g. Alcohol is the second most energy dense nutrient, providing 7kcal (29KJ)/g. Protein provides 4kcal (17kJ)/g Carbohydrate (starch and sugars) is the least energy dense nutrient, providing just 3.75kcal (16kJ)/g. [A value of 4 kcal is used for food labelling purposes.]

Measuring energy intake Energy intake is often measured in joules (J) or kilojoules (kj) but can also be measured in Calories (kcal). 1 kilojoule (kj) = 1,000 joules 1 megajoule (MJ) = 1,000,000 joules 1 kilocalorie (kcal) = 1,000 calories, or 1 Calorie To convert from one unit to another: 1 kcal = 4.184 kj 1 MJ = 239 kcal How many kj will a 2000kcal diet provide?

Energy expenditure Energy expenditure = BMR x Physical Activity Level (PAL) The actual amount of energy needed varies from person to person and depends on their basal metabolic rate (BMR) and how active they are.

Basal metabolic rate The basal metabolic rate (BMR) is the rate at which a person uses energy to maintain the basic functions of the body breathing, keeping warm, keeping the heart beating when at complete rest. An average adult will use around 1.1kcal each minute just maintaining these functions and BMR differs from one person to the next, both within a population and between population groups.

Physical activity In addition to their BMR, people also use energy for movement of all types. The amount of energy a person uses to perform daily tasks varies depending on factors such as his or her weight (the heavier a person is the more energy is required for movement) and their physical activity level. An estimate of the amount of energy an individual will need can be calculated by multiplying their BMR by a factor appropriate to the amount of activity that person does (known as the Physical Activity Level (PAL)).

Physical activity levels (PAL) A PAL of 1.4 is associated with a very low level of physical activity at work or during leisure time. This applies to a large proportion of the UK population. In contrast, a PAL of 1.6 for women or 1.7 for men represents moderate intensity activity, and values of 1.8 for women or 1.9 for men represent high levels of physical activity.

Energy balance In order for people to maintain their body weight, their energy intake must equal their energy expenditure. Failure to maintain energy balance will result in weight change. Energy balance can be maintained by regulating energy intake (through the diet), energy expenditure (adjusting physical activity level to match intake) or a combination of both.

Energy balance An increase in energy intake which is not matched with an increase in physical activity levels will result in weight gain (positive energy balance). Obesity most commonly results from an individual consuming more energy than they need. A reduction in energy intake which is not matched by a reduction in physical activity levels will result in weight loss (negative energy balance).

Achieving energy balance How can you achieve energy balance?

Follow a healthy diet

Eight top tips for healthy eating Base your meals on starchy foods ; Eat lots of fruit and veg; Eat more fish; Cut down on saturated fat and sugar; Eat less salt; Get active and be a healthy weight; Don't get thirsty; Don t skip breakfast.

Be active! To maintain a basic level of health, children and young people aged 5 to 18 need to do: at least 60 minutes of physical activity every day this should range from moderate activity, such as cycling and playground activities, to vigorous activity, such as running and tennis. on three days a week, these activities should involve exercises for strong muscles, such as push-ups, and exercises for strong bones, such as jumping and running.

Be active! To stay healthy, adults aged 19-64 should try to be active daily and should do: at least 150 minutes of moderate aerobic activity such as cycling or fast walking every week, and strength exercises on two or more days a week that work all the major muscles (legs, hips, back, abdomen, chest, shoulders and arms). Or: 75 minutes of vigorous aerobic activity, such as running or a game of singles tennis every week, and strength exercises on two or more days a week that work all the major muscles. Or: A mix of moderate and vigorous aerobic activity every week. For example, two 30-minute runs plus 30 minutes of fast walking equates to 150 minutes of moderate aerobic activity, and strength exercises on two or more days a week that work all the major muscles.

Be active How can we be more active? Make activity part of every day routine walk or cycle to school, take the stairs instead of the lift. Find a type of activity you enjoy the more you enjoy it, the more likely you are to do it. Reduce the amount of time spent being sedentary. Get active with a friend join a club together or go for a walk while you catch up.

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