1. Draw the digestive system.
Then describe it in one sentence.

2. Digestive System Applying the Principles of Nutrition to a Physical Activity Programme

3. Learning outcomes By the end of this session you will:
Describe two types of digestion: mechanical and chemical
Name and describe the main functions of each section of the alimentary canal:
Mouth
Oesophagus
Stomach
Small Intestine
Large Intestine (colon)
Describe how fats, proteins and carbohydrates are digested and absorbed, and the main enzymes involved
Discuss the role of dietary fibre in efficient digestion and elimination of waste from the body
Recognise when to refer a client to their GP for dietary advice

5. Two types of digestion
Mechanical (physical): e.g. chewing, peristalsis, etc.
Chemical: e.g. saliva, hydrochloric acid, digestive enzymes, etc.

6. Mouth Mechanical: Chewing (mastication) - food is torn/ground by teeth
Tongue rolls food into small balls that are easy to swallow
Chemical:
Moistened with saliva
Salivary amylase, which starts a chemical breakdown of starchy carbohydrate into simpler sugars
No chemical breakdown of fat or protein in the mouth
The tongue also allows you to experience taste

7. Oesophagus Mechanical:
‘Peristalsis’. Peristalsis is rhythmical waves of muscle contractions which help push food along the alimentary canal
Chemical:
There is no chemical breakdown in the oesophagus

8. Stomach
Mechanical:
Peristalsis continues. This churns and mixes food in stomach
Chemical:
Hydrochloric acid breaks down food into a liquid ‘chyme’
Digestive enzymes start to break down nutrients (e.g. pepsin breaks down proteins)
Small molecules such as water, alcohol and some medicines (e.g. aspirin) can be absorbed into blood

9. (Duodenum, Jejunum, Ileum)
Small intestine
(Duodenum, Jejunum, Ileum)
Mechanical:
Peristalsis continues, moving food along small intestine
Chemical:
More digestive enzymes break down nutrients (e.g. bile emulsifies fats)
Complex structure of nutrients is broken down into usable components
Main nutrients (fats, carbohydrates, proteins, vitamins, minerals, water) are absorbed into blood
Remainder (waste) enters large intestine

10. Large intestine (Colon) Mechanical:
Peristalsis continues, moving food along large intestine
Waste (faeces) is passed from colon to rectum and then expelled from the body
Chemical:
Partial breakdown of soluble fibre (cellulose)
Re-absorption of remaining water from undigested food

11. Dietary fibre Important for:
Efficient digestion (keeps food moving through gut)
Efficient elimination of waste. Fibre retains water in colon which adds bulk to faeces, making it easier to eliminate.
Helps to prevent constipation.
May decrease risk of bowel cancer

12. When to refer Refer a client to their GP if:
They have a condition or suspect they have a condition which may be affected by their diet. e.g.
Food intolerance
Food allergy

13. Healthy Eating Guidelines Applying the Principles of Nutrition to a Physical Activity Programme

14. Session aims
Identify dietary targets in the UK for fats, proteins and carbohydrates in relation to the provision of energy
Understand that some individuals may need more or less of a given nutrient
Describe the national food guide (Eatwell Plate)
Understand how the national food guide provides simple, healthy eating advice in a way consumers can understand
Describe standard portion sizes for each food group
Explain where to access reliable sources of nutritional information

15. UK dietary targets Based on total energy intake:
Fats = no more than 35% (not more than 11% saturated, 13% monounsaturated, 6.5% polyunsaturated)
Proteins = %
Carbohydrates = 50% (predominantly unrefined complex carbohydrates)

16. UK dietary targets
Some individuals may require more or less of a given nutrient, for example:
Individuals who require higher or lower energy intakes e.g. very active or very sedentary lifestyles
Pregnancy/lactation
The elderly
Fat loss

17. The national food guide

18. The national food guide
Intended to provide simple, healthy eating advice in a way consumers can understand
Gives key messages in terms of ‘quantity’ and ‘quality’ as presented in the Eatwell Plate

19. Healthy eating guidelines (NHS livewell)
Base your meals on starchy foods
Eat lots of fruit and veg
Eat more fish
Cut down on saturated fat an sugar
Try to eat less salt: <6g/day
Get active and try to be a healthy weight
Drink plenty of water
Don’t skip meals

20. The five food groups Food Group Recommended Intake
Bread, cereals and potatoes
Unrefined, fibre rich complex carbohydrates
Fruit and vegetables
Variety, fresh, green-leafy and brightly coloured
Meat, fish and alternatives
Include a variety of non-animal foods, oily fish, nuts and seeds
Dairy
Include some lower fat alternatives
Foods and drinks high in fat and sugar
Limit their consumption; opt for vegetable or olive oil when cooking.

21. The five food groups How much of each food group should we eat?
Depends on energy requirements

22. Guideline daily amounts
Male
Female
Energy
2500kcals per day
2000kcals
Carbohydrate
50% of daily energy
Total fats
Not more than 35%
Saturated fats
Not more than 11%
Polyunsaturated fats
6.5%
Monounsaturated
13%
Protein
10-15%
Summary of DRVs for Energy, Carbohydrates, Fats and Protein for UK Adults (19-50 years)

23. Guideline daily amounts
Exact GDAs depend on how active you are…
Male (kcal/day)
Female (kcal/day)
Sedentary
2200
1600
Average
2500
2000
Active
2800
Very Active
3000

24. Guideline daily amounts
Recommended portions of each food group to meet Eatwell Plate guidelines:
Kcal requirements
Carbs
Meat, fish etc.
Dairy
Fruit
Vegetables
High fat / sugar
1600 6
2-3
3-4
0-3
2000 7
4-5
2200 8
2500 9
2800 10 4+ 5+
3000 11

25. What is a portion? See ‘portion sizes table’ manual p132

26. Summary healthy eating guidelines
Reduce amount of saturated fats and include a wider variety of unsaturated fats
Eat less animal protein and include a wider variety of non-animal protein
Consume mainly low GI/GL complex carbohydrate
Eat more fibre-rich, unrefined starches, fruits and vegetables
Aim to consume at least 5 portions of fruit and vegetables daily
Decrease salt intake
Increase water consumption and cut down on diuretics e.g. Caffeine and alcohol
Add variety to your diet
Enjoy your food

27. Useful resources Reliable sources of nutrition information include:
NHS Choices –
British Heart Foundation –
Weight Concern –
Department of Health ‘Change 4 Life’ Campaign –
Diabetes UK –