According to Australia’s latest National Nutrition Survey, more than 2.3 million Australians (13%) aged 15 years and older say they are on a diet to lose weight or to improve their health. Weight loss is best achieved by a balanced healthy eating plan based on best evidence and expert opinion. Fad diets may or may not be based on real scientific evidence or have endorsement by the bulk of experts.
Here are some of the diets you may have heard about.
Meal replacement shakes
Meal replacement shakes are formulated to keep daily calories to a minimum. Brands of shakes can vary in their balance of carbohydrates, fats and proteins as well as vitamins and minerals. While some are designed to replace just one meal, most are intended to replace two meals each day (usually breakfast and lunch) while still eating a healthy meal for dinner. A morning or afternoon snack of fresh fruit is often recommended.
Meal replacement shakes are usually sold in a powdered form and made up into a shake by adding water or milk. There are many different types of shakes available in pharmacies and grocery and health food stores such as Celebrity Slim, Slimfast, Ultra Slim and Optislim. These shakes may also form part of a ‘diet plan’ involving other products produced by the same company.
Seek expert advice on a diet that is tailor made for you.
Evidence shows meal replacement shakes can be a useful tool in weight loss. They appeal to many people because they are portion controlled and provide a controlled way to keep overall energy (kilojoules/calories) to a minimum. Due to a significant reduction in energy, noticeable weight loss during the initial phase can be motivating. People also find shakes convenient, especially for those who regularly skip meals. Meal replacements can help with weight loss because they are usually designed to be filling, meaning people may feel less hungry between meals.
Meal replacement shakes are not all created equal. Some are medically prescribed and contain adequate nutrition, while others are easily available on supermarket shelves and may not be nutritionally complete. As most shakes are very low in energy, their use can lead to unwanted side effects such as bad breath, dizziness and tiredness. Replacing healthy meals for shakes does not teach the user about portion-control of real food which is a key element in being able to maintain a healthy weight in the long term.
Meal replacement shakes are often appealing because they are low in energy and often result in fast weight loss during the initial stages. It is important to be aware that fast weight loss from severe energy restriction is not sustainable for the long term. It can also lead to unwanted side effects such as bad breath and tiredness. If healthy eating and regular exercise habits are not followed once the diet has stopped, the weight is likely to come back on which is a common scenario for many yo-yo dieters. Before starting a meal replacement diet, DAA recommends seeking a medical assessment from your doctor and consulting an Accredited Practising Dietitian to make sure it is the best option for you.
The lemon detox diet
The lemon detox diet is a 10 to 14 day cleansing program sold in a kit form online or through pharmacies or health food stores. It involves consuming six to nine glasses each day of lemon detox drinks (a mix of 20mls of syrup, 20mls of lemon juice, a pinch of cayenne pepper and 250ml of water), a laxative senna tea in the evening and a sea salt drink in the morning. People on this diet are also advised to drink one to two litres of water each day. No other meals, snacks or foods are allowed, and the general suggestion is that exercise should be avoided. It is generally a low-kilojoule diet designed to cleanse the body naturally while taking a break from solid food.
Despite its popularity, DAA could not highlight any positive nutritional aspects of this diet.
One warning sign that this diet is severely low in nutrition and energy is that it does not recommend exercising. As a result of severe energy restriction, the body will go into starvation mode stripping your carbohydrate and fluid stores, and stripping muscle. Despite what the scales may say, most of the weight lost on this diet is fluid and carbohydrate and likely to be put straight back on once you finish. This is one diet that is impossible to sustain in the long-term.
This diet does not provide your body with the essential nutrients it needs to function. You may lose weight (from your body’s fluid and carbohydrate stores) but it will be short-lived once you revert to eating normal foods and drinks. The body has an amazing detox system – your lungs, liver and kidneys do this every minute of every day. If you want to ‘detox’, nourish your body by cutting down on fatty, highly-processed foods, alcohol and caffeine, and eat a balanced diet ensuring you include plenty of fruit, vegetables, wholegrains and water.
The Dukan diet
The Dukan diet is a low-carbohydrate (carb), high-protein diet. There’s no limit to how much you can eat during the plan’s four phases, providing you stick to the rules of the plan. During phase one, you’re on a strict lean protein diet for an average of five days to achieve quick weight loss. This is based on a list of 72 reasonably low-fat, protein-rich foods such as chicken, turkey, eggs, fish and fat-free dairy. Carbs are off limits except for a small amount of oat bran. Unlike the Atkins diet, Dukan’s phase one bans vegetables and seriously restricts fat. The next three phases see the gradual introduction of some fruit, vegetables and carbs and eventually all foods. The aim is gradual weight loss of up to 1kg a week, and to promote long-term weight management. There’s no time limit to the final phase which involves having a protein-only day once a week, and participating in regular exercise.
Many people find this diet easy to follow with no calorie/kilojoule counting required. Some nutrition principles are in line with Australian dietary recommendations including limiting processed or highly-refined carbohydrates and excess fats, encouraging plenty of vegetables and lean protein, as well as regular exercise and drinking water.
Rather than a moderate approach to healthy eating, this diet strictly limits carbohydrate foods. As per the Dietary Guidelines for all Australians for healthy eating, carbohydrate foods are an important part of a healthy diet. They provide energy, fibre and other vitamins and minerals. Diets that restrict nutritious food groups can be socially isolating and are difficult to stick to for the longterm.
While the Dukan diet has some good features, such as promoting fruit and vegetables, lean meat and fish, it excludes nutritious core foods such as breads and cereals, and relies heavily on protein. DAA is concerned that it encourages restrictive eating which is not sustainable in the longterm. By banning certain nutritious foods, followers of this diet will be at a greater risk of falling short on important nutrients such as calcium.
The Atkins diet
The Atkins diet is a low-carbohydrate (carb), high-protein weight loss program which starts with a low-carb diet designed for rapid weight loss (up to 6kg in two weeks). This lasts for at least two weeks depending on your weight loss goal. During this phase, you’re on a protein, fat and very low-carb diet including meat, seafood, eggs, cheese, some vegetables, butter and oils. In contrast to the Dukan diet, Atkins allows unlimited fat and some vegetables, such as capsicums, cucumber and iceberg lettuce, during phase one. During the next three phases, the weight loss is likely to be more gradual and regular exercise is encouraged. More carbs, fruit and vegetables are introduced to your diet with the aim of working out what your ideal carb intake is to maintain a healthy weight for life.
This diet can be attractive because it encourages unlimited amounts of fats (even the ‘unhealthy’ saturated type) and protein. The thought of a diet that includes butter, bacon and sausages can be very appealing to some people. The diet also provides structure which helps many stay on track. The reduction in energy from excluding carbohydrates means people can often (in the initial stages) lose weight quite quickly, which is motivating.
Lack of carbohydrates can lead to tiredness, bad breath and constipation. The unlimited fat intake can also put people at greater risk of high blood fats and cardiovascular disease (such as heart attack and stroke). This diet also excludes certain fruits and vegetables nutritious foods that many Australians are not eating enough of to maintain good health. Any diet that singles out certain foods (such as particular vegetables) over others makes life difficult and needs to be treated with caution.
This diet is not nutritionally balanced. It does not contain the right amounts of fat, protein and carbohydrate to make it sustainable or in line with national dietary recommendations. Putting restrictions on healthy foods, such as fruits and vegetables, can confuse people and put them at increased risk of nutrient deficiencies. Less than 4% of Australians over the age of 12 years eat the recommended amounts of vegetables, and only one third eat the recommended amount of fruit. Any diet should encourage a variety of all fruits and vegetables each day rather than restricting them.
The liver cleansing diet
This diet was made famous in 1996 when Dr Sandra Cabot’s book The Liver Cleansing Diet was published. It is an 8-week eating plan to combine foods for efficient metabolism, weight control and liver repair. It is based on the premise that the liver is the major fat-burning organ in the body, and by following this diet your metabolism will improve which will lead to fat being burned.
The diet is broken down into three phases – the first two weeks, the middle four weeks and the last two weeks. About 40% of the diet is raw fruits and vegetables. Sources of protein include legumes, grains, seeds, nuts, fish and seafood as well as free range chicken and eggs. No other meats or dairy products can be consumed, although different breads and pastas are allowed, as are monosodium glutamate (MSG)-free condiments (MSG is a common food additive), but no unhealthy fats such as margarines or processed vegetable oils. Each phase starts with drinking two large glasses of purified water with the juice of a fresh lemon, lime or orange to cleanse the liver, followed by raw vegetable juice, every morning. It also recommends various supplements and herbs to support liver health.
This diet follows many scientifically proven healthy eating guidelines such as opting for minimally-processed foods, choosing water as a drink, eating more high-fibre foods (such as legumes and wholegrains) and eating plenty of fruits and vegetables.
The diet makes many claims that are not backed by sound scientific evidence. Excluding dairy products without adequate calcium replacements can lead to a greater risk of osteoporosis. Lean red meat can provide the body with a good source of iron, protein and other vitamins and minerals. The recommendation to purchase products, such as supplements, can be costly and will not suit everyone.
This diet encourages many well-established dietary recommendations that are in line with national dietary guidelines. DAA agrees that a diet high in fruits and vegetables, wholegrains and lean protein is good for your health and your liver. However, there is no need to cut out nutritious foods such as dairy products and lean red meat to achieve good health. The most solid evidence to maintain a healthy liver is to limit saturated fat, increase fibre and lose weight by exercising and eating according to your energy needs.
Guidelines and expert advice
Dietary Guidelines for all Australians can be found at www.eatforhealth.gov.au.
Before you turn to a ‘detox’, ‘cleanse’ or ‘diet’ to lose weight and improve your health, the DAA advises people to seek expert advice on a diet that is tailor-made for them. There is a list of Accredited Practising Dietitians on their website at daa.asn.au.
Warning signs that a diet might be a fad include:
- the diet bans certain foods or food groups
- the diet promises quick, dramatic results
- the diet encourages miracle pills or potions
- the diet claims a ‘one-size-fits-all’ approach to weight loss.
The Healthy Weight website offers healthy eating tips and information on physical activity and nutrition to help you achieve and maintain your healthy weight. It is an initiative of the Australian Government and can be found at www.healthyactive.gov.au.
You may also like to take part in 'Australia’s Healthy Weight Week' which is a DAA initiative held in the last week of January each year. More information can be found at www.healthyweightweek.com.au.
Last reviewed: October 2016