Nutrition journey – PART 1.1 Glycemic index

Introducing the Glycemic Index (GI)

The glycemic index (GI) ranks carbohydrates on a scale from 0 – 100 according to the extent to which they raise blood glucose (sugar) levels after eating. Foods with a high GI are those which are rapidly digested and absorbed, this results in fluctuations in blood sugar levels. Low-GI foods, slows digestion and absorption, produce gradual rises in blood glucose (sugar) and insulin levels, and have significant benefits for health. Low GI diets have been shown to improve:

  • Glucose and lipid levels in people with diabetes (type 1 and type 2).
  • Weight control because they help control appetite and delay hunger
  • Low GI diets also reduce insulin levels and insulin resistance
  • Athletic performance when consumed within the correct timeframe.
GI classification scale:
  • Low:        <55
  • Medium:  56-69
  • High:     >70

Introducing the Glycemic Load (GL)

Glycemic Load (GL) is a measure of quality (GI rating) and quantity (amount) of carbohydrates in food. Thus GL takes into consideration the amount of GI carbohydrates consumed.

GL is calculated as follow: GI of food x amount of carbohydrate (g) in that food multiplied by 100

For instance, an apple: GI value of an apple is 36 and a serving of apple contains 15g of carbs thus: 36 x 15 multiplied by 100 = 6

GL can be classified as:
  • Low:        <10
  • Medium:  11-19
  • High:       >20

Therefore it is possible to consume high GI foods in a healthy diet if it is in quantities below 10 GL .

Simplifying the term GL: GL indicates how much of a carbohydrate you could consume to have a stable effect on blood sugar levels, thus you could consume a lot more of low GI food before having an effect whereas high GI food should only be eaten in small quantities.

GI and health

Diabetes

Numerous studies indicated that low GI diets decrease the risk of developing type 2 diabetes but also assist in improving management of diabetes.

Low GI diets:

  • Improve blood glucose levels
  • Reduce insulin resistance
  • Improve blood cholesterol
  • Reduce your risk of developing type 2 diabetes
  • Lower insulin levels makes fat easier to burn and less likely to be stored

Top tips to help you manage your blood glucose:

  • Choose low GI food regularly, medium GI food in moderation or only sometimes, high GI food in very small quantities or very seldom.
  • Always swop white starch and cereal for whole-grain.
  • Exercise regularly: Physical activity every day will help improve your blood glucose levels and general health.    

Heart Health

A low GI diet can improve heart health by:

  • Reduce blood glucose levels after a meal
  • Improving the elasticity of blood vessel walls and blood flow
  • Improving blood cholesterol levels
  • Reducing the risk of atherosclerosis by reducing inflammation
  • Aiding abdominal fat reduction

Reduce Breast Cancer Risk

Studies indicates that consuming a high GI diet for >5 years may increase the risk of breast cancer by 8% compared with a low GI diet.

 

Healthy Pregnancy

While we all benefit from eating well, during pregnancy it becomes even more important. The quality of diet during pregnancy can affect a child’s future health, long after being born.  A poor diet during pregnancy may predispose a child to developing obesity or diabetes when older; whereas a good diet can protect against it. Studies indicate that a mother’s diet during pregnancy can define her child’s metabolism in both good and bad ways.

Being pregnant do increases nutritional needs, but mostly to less extent than expected. In fact, energy needs during the1st  trimester remain the same as previous needs. In the second trimester 20% more energy is necessary and in the third trimesters 25-30%. However, your need for certain nutrients (such as iron and folate) increases significantly so it is extremely important to fill up on nutrient dense food. 

Gestational Diabetes
Gaining the right amount of weight during pregnancy is important, too much will increase your risk of gestational diabetes and other pregnancy complications. Gestational diabetes (GDM) is a form of diabetes that occurs during pregnancy and usually disappears after the birth but may reoccur in the next pregnancy. GDM occurs when the hormones made by the placenta during pregnancy stop the body’s own insulin from working properly, causing blood glucose levels to rise.  As glucose is the main fuel for your baby’s development, if your levels are too high, your baby may grow too fast, be born with excess body fat and is at risk of developing type 2 diabetes down the track.

Reducing the GI of your diet is one of the safest and most effective ways of ensuring the baby grows at a healthy rate. Unlike many diets, a healthy low GI eating plan is not difficult and is completely safe during pregnancy. It is not restrictive and doesn’t require any major food groups or nutrients to be cut out. It benefits both mother and child

GI and wellbeinig

Weight management

Achieving healthy weight and the maintenance thereof is essential to overall health and wellbeing. A healthy low GI diet will contribute to reaching healthy weight and maintaining it. Low GI eating plan won’t cause unsustainable short-term weight loss by cutting out a certain food group or nutrient, it doesn’t require you to cut out carbs or to go hungry. It is about filling up on low GI food, and swapping as much possible high GI foods for low GI foods.

A low GI diet assists you in reaching and maintaining your goal weight by helping you overcome hunger, burn fat and maintain metabolic rate.

  • Overcoming hunger

    Low GI foods take longer to digest and help you feel satisfied by activating appetite suppressors. In contrast, high GI foods cause stress hormones to be released, which stimulates appetite.

  • Accelerate fat burning

    High GI foods cause a rapid increase of blood glucose that signals the body to release a burst of the hormone insulin. A large burst of insulin will leave you fatigued (feeling tired), hungry, craving sugar and also decrease the tempo at which the body burns fat. Eating low GI carbohydrate foods causes a steady rise of blood glucose, which only results in a small and gentle rise in insulin. Small increases in insulin keep you feeling full, energized for hours and encourages the body to burn fat.

     

  • Maintain metabolic rate

    Popular diets require cutting down dramatically on food intake or food groups rather than swap to healthier choices. Unfortunately, this usually leads to a loss of lean muscle and organ (body) mass which slows down your metabolic rate, leading to weight re-gain in the long-term. A healthy low GI diet encourage maintenance of lean body mass, and consequently maintain metabolic rate, leading to sustained healthy weight. Also combine this with weight bearing exercises such as walking that build strong bones and strengthen your muscles so they burn fat more efficiently. Aim for 30 – 60 minutes of moderate paced exercise every day, on top of an active lifestyle.

Increased performace

Increase Mental Performance

Low GI foods provide a steady supply of fuel (glucose) to the brain, improving cognitive performance. As discussed previously, our brains can only use glucose as energy fuel and have no reserves, so it is important that a constant supply of glucose is provided throughout the day. Studies done on learners has proven that eating a low GI breakfast is associated with better learning and school performance trough improving concentration.

Maximize Sports Performance

As we also discussed in our previous discussion on carbohydrates are the body’s main source of fuel is carbohydrate, which in the simplest form is glucose. When you consume carbohydrates it is utilized for energy, those carbohydrates that are not used up are stored mostly in your muscles and liver as glycogen. When your body needs fuel, it quickly breaks down the glycogen into glucose for energy.

For decades athletes have been using GI science for their sports preparation and recovery. Low GI foods are broken down slowly, steadily releasing glucose into your system over time, providing a stable, long-during energy release, thus perfect to consume prior to endurance aerobic exercises. Low GI foods have proven to extend endurance when eaten 1 – 2 hours before prolonged strenuous exercise. While high GI  foods could be beneficial prior to high intensity short duration (anaerobic) exercises for a rapid burst of energy. 

 

Reccomendations

1. Swap high GI foods for low GI foods. SEE LIST BELOW

2. Eat at least one serving of a low GI carbohydrate food at each meal, and choose low GI snacks.

3. Keep your eye on serving sizes. Eating too much food, even if it’s a healthy choice, isn’t good for you.

4. The ideal meal: Aim for half vegetables/salad, quarter lean protein and quarter low GI carbohydrate.

  • Vegetables/salad: aim to eat at least five serves of vegetables every day preferably with three or more different colours.
  • Protein: good sources include lean meat, skinless chicken, fish, seafood, eggs, milk, yoghurt, cheese, legumes or tofu.
  • Lower GI carbs: try pasta (cooked al dente), low GI white rice, pearl cous cous, or quinoa.

5. Go grainy: Choose grainy breads (where you can actually see the grains) over white bread

6. Get a good start: Replace highly processed breakfast cereals with natural muesli, traditional porridge oats or cereals that carry the GI Symbol.

7. Love legumes! Include legumes like beans, lentils and chickpeas in your meals two or three times a week, or more often if you are a vegetarian.

8. It’s all about balance: Don’t completely cut out high GI options, the trick is to combine them with low GI options to achieve a moderate GI.

9. Smart Snacking: When it comes to snacking, go for fresh fruit, nuts and yoghurt. Avoid refined flour products like cookies, crackers and biscuits.

10. Wonderful Water: Make water your first choice. Avoid sugary drinks and drink no more than one to two glasses of alcohol a day.

Easy and healthy low GI breakfasts

  • Low GI fruit or seed bread with a tsp low fat humus OR omega3 rich margarine and Bovril/marmite spread.
  • Wholegrain, low GI breakfast cereals with reduced or low fat milk and fruit.
  • Natural muesli with reduced or low fat milk.
  • Low GI bread with a teaspoon of natural peanut butter
  • Low GI bread with baked beans.
  • Low GI bread with a poached or non-stick pan fried egg.
  • Low fat yoghurt with low GI fruit.
  • Glass of Milo® with reduced fat milk and a piece of low GI fruit e.g. a pear or apple
  • Banana Smoothie with reduced fat yoghurt.

Top up with a healthy low GI lunchbox some ideas include:

  • Add a piece of low GI fruit e.g. apple, pear, grapes.
  • Swap the bread for a low GI.
  • Also include a protein source like biltong or chicken in the sandwich or within the lunchbox.
  • Try low fat hummus with carrot sticks.
  • Add some dairy – a tub of reduced fat yoghurt. Hint: Freezing helps keep it fresh and the rest of the lunch cool.

Healthy low GI foods provide longer lasting energy to keep you going throughout the day.

Breakfast lineseed toast with egg and avo salsa

A delicious, simple breakfast idea on Low GI linseed bread

Ingredients:
1/4 avocado, peeled & cubed
1/2  roma tomato, seeded and finely diced
1 TBS lime juice
1 TBS finely diced coriander
1 poached eggs
1 Toasted linseed bread
 
 Method:
To make the salsa: combine avocado, tomato, lime juice.
Coriander in a small bowl and mix lightly. 
Serve salsa with a poached egg & toast.

Strawberry yogurt crunch

This is a great breakfast recipe or have a smaller portion as snack/dessert.

Although nuts and seeds are high in fat, research shows that people who eat them often tend to be slimmer and healthier. This is because the fat in nuts and seeds is mainly unsaturated (the healthy kind of fat), we probably don’t absorb all of it, and they are packed with other essential nutrients and fibre.

Ingredients:
10g mixed raw nuts
5g sunflower seeds
5g pumpkin seeds
150g low fat natural yoghurt
1 small mango, sliced
50 g strawberries, sliced

1 TSP pure floral honey

Method:
  • Heat a non-stick frying pan over medium heat and add the raw nuts and seeds. Dry-fry them for 1–2 minutes, stirring continuously until browned (take care as the nuts will burn very quickly). Remove from the heat and, when cool enough to handle, roughly chop with a large knife.
  • Take four glasses and spoon a little yoghurt into the bottom of each one. Divide the mango slices between the glasses, top with another layer of yoghurt, then finish with a layer of sliced strawberries. Drizzle the honey over the strawberries and sprinkle the toasted nut and seed mixture over the top.

Tuna, corn and celery sandwich

A classic combination, full of protein and low GI carbohydrates.

Ingredients:

60g tuna, drained
¼ cup canned sweetcorn
¼ stick of celery, finely chopped
¼ avocado, chopped
1 slice of low GI seed bread

Fresh rocket leaves

 Method:

Combine all ingredients gently and spread over 1 slices of bread.  Top with rocket leaves and another slice of bread.

Tarragon chicken and beans

Ingredients

Cook and spray
120g (boneless, skinless chicken thigh fillets, fat trimmed)
½ red onion, cut into wedges
½ celery stalk, sliced
40ml dry white wine
1 small handful tarragon leaves
½ can borlotti beans, rinsed and drained
¼ cup reduced-fat evaporated milk
¼ cup frozen peas

¼ cup broccolini, steamed 

Method:
Spray a large pan with cook and spray and place over medium heat. Cook the chicken for 2 minutes on each side or until browned.
Transfer to a plate. Add the onion wedges and celery to the pan and cook, stirring, for 2 minutes or until the onions have softened.
Pour in the wine and stir until combined. Return the chicken to the pan, cover and cook for 15 minutes or until the chicken is cooked through.
Add the tarragon leaves, borlotti beans, evaporated milk and peas to the pan and cook for 10 minutes or until the sauce is thickened and heated through.
Sprinkle the chicken and beans with the extra tarragon and serve with the broccolini.

Garlic and rosemary chicken tray

Ingredients:
Cook and spray
1 small sweet potatoes, peeled, 
1 skinless chicken drumsticks 
1 skinless, boneless chicken thigh 
Zest and juice of 1 orange, plus extra zest, to garnish
1/2 red onions, cut into wedges
1/4 cup roasted red capsicum
3 TBS balsamic vinegar 
1 sprig rosemary
1 garlic bulb, broken into cloves

1/2 cups chopped silverbeet

Method:

Preheat oven to 200°C. Spray a large ovenproof baking dish. Cook potato in boiling water for 5 minutes; drain. Cut several slits in chicken pieces and toss with orange zest. Place potato, onion and capsicum in a large bowl. Mix orange juice with vinegar in a small bowl; add to vegetables and toss to coat. Place vegetables in prepared baking dish and top with chicken. Break rosemary into small sprigs; place two-thirds into chicken slits. Add garlic and remaining rosemary to dish. Bake for 45 minutes, tossing halfway through. Stir through silverbeet in final 10 minutes of cooking time. Season with freshly cracked black pepper; garnish with extra zest and serve.

Herb crusted fish

Ingredients:

1 Wholegrain & Oats Bread slice
Chopped parsley and chives
Lemon zest
1 TSP olive oil
Pepper, to taste
1 fish fillets (hake)

Lemon wedges, to serve

Method:

Pre-heat oven to 220°C. In food processor combine bread, parsley and chives until they make a fine breadcrumb. Add lemon zest, olive oil and pepper to taste .Place fish fillets onto a lightly greased oven tray and evenly coat the fish with the bread crumb mixture. Bake for 10-15 minutes or until fish is cooked through and crust is golden brown. Serve with lemon wedges and salad.

  • References

    • Brand-Miller, et al. 2009
    • Chang, et al. 2012
    • Livesey, et al. 2013
    • Louie, et al. 2013
    • Mica, et al. 2010
    • Thomas, et al. 2007
  • Usefull links

    • www.glycemicindex.com
    • www.gisymbol.com

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