Stephanie Pirotta , Jean Hailes for Women’s Health dietitian, says the organisation never recommends specific diets; instead, it’s about balanced, healthy eating.
But with so much talk at the moment around various diets that encourage fasting in some form—such as the 5:2 Diet and the 16:8—it’s important to look at the health realities of the practice, says Ms Pirotta.
Put simply, fasting diets involve consuming few or no calories over a particular time period. One of the most popular ways of fasting is intermittent fasting, which is low or no calorie consumption for a defined number of hours or days (e.g. 18-48 hours) during certain days of the week. Over an average week this might involve having the recommended number of calories five days a week, and reducing calorie intake to 25-40% of the recommended amount, two days a week. For women, that’s usually around 500-800 calories a day (as a guide, half a medium avocado is around 150 calories). Alternatively, periodic fasting involves constant low-calorie consumption; around 750-1100 calories a day over a longer duration (e.g. 2-21 days).
Does fasting work?
In a recent U.S annual review of 16 studies on intermittent fasting, 11 of these studies reported weight loss.But only two found significant weight loss in those following some type of fasting plan.
“For some people, intermittent fasting can lead to weight loss because it improves a person’s overall eating habits and reduces their daily energy intake,” says Ms Pirotta.
“It can also lead to a decrease in ‘bad’ cholesterol and insulin levels, which can help manage or reduce the risk of chronic diseases such as type 2 diabetes and cardiovascular disease.”
Of course, there are still drawbacks. Fasting may lead to fatigue, headaches and constipation and it’s not recommended for the elderly, frail, pregnant women and people with diabetes. There’s also always the possibility that some people might overeat on their non-fasting days, which can prevent weight loss over time. “Larger and longer-running human trials are needed to confirm the impact of intermittent fasting on health,” says Ms Pirotta.
Intermittent fasting for no longer than 48 hours can improve the metabolism and its ability to change from the body’s carbohydrate or protein stores to fat stores (when energy intake is low) to help ensure the body has a constant energy supply. This is what helps reduce weight.
However, longer periods of energy restriction can lower your metabolism to conserve your energy. “This is commonly what leads to weight regain when starting to eat regularly again after following a low energy diet for a long period of time,” says Ms Pirotta.
“There’s still very little evidence to show that intermittent fasting is any more beneficial that a daily calorie-restriction plan in the long term. It’s best to follow an eating plan that works best for you and your lifestyle, so that it’s realistic and will be effective,” she says.
She advises seeing an accredited practising dietitian or your GP to choose a diet plan that suits your individual health needs and lifestyle.
A HEALTHY LOW-CALORIE RECIPE
Created by Jean Hailes for Women’s Health naturopath, Sandra Villella
Red lentil tomato capsicum soup (130 calories per serve)
Serves 6 (note: portion sizes are important)
Prep 10 mins
Cooking 35 mins
- 1 tsp olive oil
- 1 medium onion, finely chopped
- 1 clove garlic, finely grated
- 2½ cm fresh ginger, finely grated
- 2 tsp ground garam masala
- 1 tsp ground turmeric
- 1 medium capsicum chopped
- 1 x 400g tin chopped tomatoes
- 150g red lentils
- 3 vegetable stock cubes, dissolved in 1.5 litres of boiled water
1. Saute the onion, garlic and ginger in the olive oil until the onion is soft. Because of the small amount of oil used, add a teaspoon or two of water occasionally to prevent from sticking
2. Add the spices and mix well until the onion is well coated.
3. Add capsicum and cook for another minute or two.
4. Pour in the tomatoes, lentils and vegetable stock and bring to the boil.
5. Reduce to a simmer and cook for 30 minutes, stirring occasionally, as lentils have a tendency to catch on the bottom of the pan.