When it comes to pop diets, separate fact, fat and fad

Gimmicky diets often result in weight loss at first, before leaving a person less healthy – and heavier – down the road; learn how to spot shonky programs.

If the magazine covers in your waiting room are anything to go by, Australians are obsessed with dieting.

Paleo, low-carb, detox, raw, clean eating, et cetera. Every week there seems to be a new ‘diet’ craze claiming to revolutionise the way we eat and offering the promise of rapid weight loss.

Statistics show that during 2011–12, more than 2.3 million Australians reported dieting to lose weight or for health reasons, the majority of whom were aged 51–70.

Judging by the wave of ongoing trends, it’s unlikely fad diets will disappear any time soon.

Nurses in many settings are well positioned to be asked about such diets, so it is helpful to know if there’s any substance to their claims.

How to spot a fad diet

Accredited Practising Dietitians (APDs) define fad diets as any eating plan that promotes results, such as fast weight loss, without the scientific evidence to support its claims.

Common features of fad diets include:

• Celebrity endorsements.
• Strict food rules.
• Exclusion of an entire food group.
• An unrestricted amount of a certain food
• A ‘magical’/ newly discovered food or food combination.
• A commercial product with enthusiastic testimonials and scientific jargon making it sound almost too good to be true (and where the small print says ‘in conjunction with a healthy eating plan and exercise’).

Do they work for weight loss?

The science of weight loss is simple: consume fewer kilojoules than your body expends.

Fad diets may appear to work initially, however, this is usually due to a decrease in kilojoule intake upon commencing a new eating plan. Many fad diets become difficult to continue and are unsustainable in the long term.

A recent meta-analysis comparing numerous ‘diets’, concluded that regardless of the dietary approach, they were all equally effective in achieving significant weight loss (an average of 8 kilograms) over the first six months. They were also equally ineffective in the long term, with study participants ultimately regaining weight.

Successful weight loss and eating for good health comes down to modifying eating behaviour. It is essential that any eating pattern meets nutritional needs, is practical and is suitable for individual lifestyles. The ultimate goal is to achieve and maintain a nutritionally balanced healthful eating pattern that can be sustained in the long term. Regular physical activity is also important, especially for those wanting to lose weight.

Dangers of fad dieting

Not only are fad diets ineffective, they can also be dangerous.

• Muscle loss: whilst fad diets successfully achieve weight loss results in the short-term, evidence suggests that the weight lost is mostly lean muscle and water, with little effect on body fat. Breaking down muscle leads to a loss of water, creating the illusion of rapid weight loss, and a reduced metabolic rate. As a result, when the diet is stopped, it is easier for the body to regain fat mass than it was prior to going on the diet. Older adults are particularly susceptible, as it is more difficult for them to regain lost muscle mass and thus strength.
• Nutritional imbalance: rarely are fad diets nutritionally balanced, putting participants at risk of not getting certain nutrients. For example, the paleo diet (also known as the caveman diet or Paleolithic diet) recommends avoiding calcium-rich dairy, and fibre-rich grains and legumes. A recent review of the paleo diet advocated for GPs to counsel patients following the Palaeolithic diet about adequate calcium intake, especially those at higher risk of osteoporosis.
• Hypoglycemia: people living with diabetes managed with insulin or a sulphonylurea medication also need to be wary of fad diets. Fad diets that leave out foods containing carbohydrates may place them at higher risk of hypoglycaemia, particularly if medication is not adjusted.
• Eating disorders: dieting is the single most important risk factor for developing an eating disorder. Yo-yo dieting affects body image and self-esteem and contributes to mental health issues such as depression and anxiety.
• General poor health: fad dieting can also lead to dehydration, nausea, diarrhea, lethargy, headaches, dizziness and bad breath, which are not good for anyone.

What’s the opposite of a fad diet? A dietary pattern. The origin of the word 'diet', comes from the Greek word diaita, meaning ‘a way of life’.

A review of seven basic dietary patterns (low carb, low fat, low GI, Mediterranean, mixed/balanced, Paleolithic and vegan) concluded that there is no one-size-fits-all approach to healthy eating, with many different ways to eat a healthy diet. The key take-home message was to eat a diet rich in plant foods, with minimal processing. This message was consistent among each eating pattern associated with both good health and prevention of diet-related diseases like type 2 diabetes, cardiovascular disease and certain cancers.

The current Australian Dietary Guidelines are an evidence-based guide to healthy eating for the entire population. They outline recommended servings from five core food groups: grain foods; vegetables and legumes/beans; lean meats and poultry, fish, eggs, tofu, nuts and seeds and legumes/beans; milk, yoghurt, cheese and alternatives; and fruit.

National Health Survey data shows most Australians do not usually meet their recommended minimum number of serves for any of these five core food groups and nearly a third of their energy intake comes from non-core or discretionary foods such as alcohol, cakes, muffins, scones, confectionery, cereal, nuts, fruits, seed bars, pastries, biscuits, soft drinks and flavoured mineral waters.

Supporting Australians paring back their eating to the basics, and encouraging them to edge out calorie-dense and nutrient poor ‘extras’ with another serve of vegetables or whole grains each day, could be the best step to healthier eating overall.

Key practice points

• An easy way to sort fact from fad is to look beyond the smoke and mirrors of celebrity endorsements and clever marketing.
• Swap paleo for Plato! Change your definition of ‘diet’ from ‘restrictive eating to lose weight’ to ‘the kinds of food that a person habitually eats’.
• There is no one-size-fits-all approach with diet. A diet needs to be individualised to help the patient stick to it and maximise chances of success, especially with weight loss and diabetes management in the long term.
• An Accredited Practising Dietitian can provide practical, expert, individual dietary advice on how to lose weight and stay healthy.

Karissa Woolfe is an accredited practicing dietitian (APD). To locate an accredited practicing dietician in your area, go to the ‘Find an APD’ section of the DAA website.

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