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Eating for energy

What’s so important about eating healthy food regularly through the day? The food you eat contains fat, protein and carbohydrates, which gives your body fuel to keep going. Eating regularly ensures you get all the nutrients you need when you need it and helps keep hunger at bay.

It also helps keep your blood sugar levels stable. When blood sugar levels drop, this can make you feel shaky, weak and nauseous. Low blood sugar levels also affect concentration, energy levels, your metabolism and mood.

How blood sugar levels affect your energy and appetite

Carbohydrates are your body’s preferred source of energy, so carbohydrate-containing foods have a big influence on blood sugar levels. Some carbohydrates are better for fuelling your body than others. Carbohydrates in sweets, biscuits, chocolate, sugary breakfast cereals and cake, for example, are quickly absorbed into the bloodstream, causing a rapid rise in blood sugar. This gives you a quick energy ‘lift’, but because it’s short-lived, blood sugar levels will soon drop again. This gives you relatively little overall benefit. In addition, these foods also tend to be high in kilojoules, increasing the risk of weight gain even in small doses.

But foods like wholegrain bread, wholegrain cereals, pasta, fruit, beans and lentils contain carbohydrates which take longer to break down and are more steadily absorbed by your body. This helps to maintain stable blood sugar levels for longer, keeping your energy levels consistent and helping you feel fuller for longer.

Eat slower burning carbohydrates

The secret to keeping blood sugar levels stable is to choose starchy foods that are low on the glycaemic index (GI). The glycaemic index tells you how quickly a particular carbohydrate-containing food will trigger a rise in your blood sugar level. The lower the GI count, the slower the carbohydrates in the food breaks down during digestion — and the slower the release of glucose into the bloodstream. Aim for foods that have a low or moderate GI count (GI around 55 and lower), such as oats, muesli, dense grainy breads, beans and lentils. Yoghurt and milk also count as low GI foods.

Besides stopping you from functioning at your best, sharp swings in blood sugar levels can affect your long-term health. Studies have shown that people who eat a lot of high-GI foods have a greater risk of developing type 2 diabetes and heart disease.

Don’t skip breakfast

For most people, blood sugar levels drop at night, so it’s important to refuel first thing in the morning. Skip breakfast and you’re more likely to snack on sugary foods later in the day. Ideally breakfast should contain about 25 percent of your daily energy intake and include a mix of low-GI carbohydrates, protein and fibre. It’s also a good opportunity to add some fruit to count toward your two serves a day.

Examples of healthy breakfast choices

Try some of these easy healthy breakfast ideas:

  • Muesli and porridge made with traditional oats are low-GI foods and are full of fibre
  • Use fruit rather than added sugar to sweeten cereal — dried apricots, kiwi fruit, bananas, berries and apple are all low GI, rich in vitamins and contain fibre
  • Dairy products like reduced fat milk and low-fat yoghurts are low GI as well as rich in protein and calcium.

Make time for lunch

Ideally lunch should be the largest meal of the day, but this isn’t always possible. Some people skip lunch entirely or grab fast food to eat on the run. It’s better to plan ahead and make a healthy packed lunch to take to work. Even a light lunch makes it less likely that you will snack on unhealthy biscuits or chocolate mid-afternoon. Eating light meals at regular intervals helps you use your energy more wisely and can assist in weight loss.

The rate at which your body uses energy is called the metabolic rate or total energy expenditure. You spend around five to 10 percent of your energy use in eating, digesting and metabolising food, another 20 percent burning kilojoules during movement and physical activity if you are a normally active person, and the remaining 50–80 percent is the amount of energy used while you are at rest, which is your basal metabolic rate (BMR).

Your BMR can be influenced by many factors including your body size, age, gender, genetic predisposition, hormones and amount of physical activity. How you eat can also affect your BMR. If you have dietary deficiencies or if you are crash dieting or fasting, your body may slow your metabolism to conserve energy. Your BMR can drop by up to 15 percent. This means you won’t use the fuel you are consuming as effectively which can lead to paradoxical weight gain.

A lunch heavy in carbohydrates may leave you feeling sluggish and sleepy in the afternoon. Eating protein-rich foods with smaller portions of carbohydrate-foods such as bread, potatoes, pasta, noodles or rice can help prevent this and keep you full at the same time. Don’t forget this is a good opportunity to add vegetables or a salad to count toward your five servings of vegetables a day.

Examples of healthy lunch choices

  • Protein-rich foods such as lean poultry or meat, oily fish (like salmon, tuna, smoked trout or sardines), eggs, tofu, nuts, low-fat dairy products, beans or lentils
  • Salads − for variety include a mix of raw vegetables, adding kidney beans, chickpeas, nuts or seeds. Or try a mix of rice, pasta or barley with raw vegetables, using low-GI rice such as basmati or Doongarra rice
  • Soup, preferably without cream
  • A wholegrain sandwich or wrap filled with a mix of lean protein-containing foods and salad vegetables
  • Rye bread, pumpernickel or wholegrain pitta bread are good slow-burning carbohydrates to go with a salad, soup or sandwich.

Smarter snacking

There’s nothing wrong with a snack to beat the occasional energy dip during the day. The trick is to go for healthy slow-burning snacks that satisfy your hunger and keep your energy levels up for longer. These include:

  • Fresh fruit in season such as apples, grapes, mandarins, pears and plums
  • Dried fruit
  • Raw vegetables, with hummus, low-fat cottage cheese or low-fat ricotta for a little something extra
  • A handful of nuts and seeds
  • A low-fat fruit yoghurt or fruit smoothie.

Drink plenty of fluids

Dehydration causes loss of concentration, dipping energy levels and headaches. It’s easy to forget to stay hydrated when you are busy. Keep your fluid levels up by drinking water, juice or herbal teas. Aim for at least six to eight glasses of fluid a day and limit your caffeine intake as large amounts of caffeine may affect hydration levels.

Further information

The Dietitians' Association of Australia

Glycemic Index (University of Sydney)


Better Health Channel. Carbohydrates and the glycaemic index. [online] Melbourne, VIC: State Government of Victoria. c1999-2010 [updated Apr 2010, accessed 2 Aug 2010] Available from:

Better Health Channel. Metabolism explained. [online] Melbourne, VIC: State Government of Victoria. c1999-2010 [updated Jun 2009, accessed 2 Aug 2010] Available from:

Dietitians’ Association of Australia (DAA). Glycaemic index. [online] Deakin, ACT: DAA. [updated 4 Dec 2009, accessed 2 Aug 2010] Available from:

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This information has been developed and reviewed for Bupa by health professionals. To the best of their knowledge it is current and based on reputable sources of medical research. It should be used as a guide only and should not be relied upon as a substitute for professional medical or other health professional advice.

Bupa Australia Pty Ltd makes no warranties or representations regarding the completeness or accuracy of the information. Bupa Australia is not liable for any loss or damage you suffer arising out of the use of or reliance on the information. Except that which cannot be excluded by law. We recommend that you consult your doctor or other qualified health professional if you have questions or concerns about your health. For more details on how we produce our health content, visit the About our health information page.

Last published 31 October 2010