The world of diets
Forget the pseudo science and celebrity endorsements, here is how to tell which diets really weigh up.
There is a plethora of different diets today. The question is which do we choose and what should we eat? ©Shutterstock/VICUSCHKA
People hear the word ‘diet’ and tend to think ‘food restriction’, but diet simply refers to an individual pattern of eating. ‘Fad’ diets are eating patterns that promote quick weight loss, cut out certain food groups and sometimes include (expensive) supplements. Their restrictiveness means they often do produce results, and subsequently become popular in the media. That is, until people realise they are not affordable, enjoyable, or effective for the long term.
You can spot a fad diet by looking at the food groups it does or does not include. Covering all groups means covering all the nutrients your body needs for long-term health. Subsequently, any diet that cuts out one or more core groups leaves you at risk of nutrient deficiencies and health issues down the track.
Guidelines differ a little from country to country, but generally go something like this:
- Bread and cereals for carbohydrates, B-vitamins and fibre
- Meat and alternatives for protein and iron (animal products for vitamin B12)
- Pulses and cereals for protein and iron
- Dairy products for calcium, protein, vitamins and minerals
- Fruit and vegetables for vitamins, minerals and fibre
- Oils and fats sometimes have their own group too, providing essential fatty acids, energy and vitamins
Diet approaches that cover all the essentials
There are countless ways to consume a diet for optimal health. With food availability, culture, education, cost and taste influencing choices, this can look very different from one person to the next. Eating patterns such as DASH1, MIND2 and Mediterranean are some of the best, recommending a variety of food across all the food groups.
Some of the diets that focus on long-term weight loss are calorie restrictive yet nutritionally sound. Commercial diets like the Mayo Clinic, Weight Watchers and Jenny Craig diets sit here, however they are often expensive and tricky to follow due to limited flexibility for different lifestyles. The kilocalorie counting they encourage is not an exact science either, nor is it a very enjoyable way of thinking about food! The Volumetrics diet for weight loss is a little different, based on the theory that people will eat the same weight of food each day. It therefore promotes low-energy density food such as fruit, vegetables, cereals, low fat dairy products and lean meat, covering all the food groups, and is not going to leave you hungry.
The ones to avoid
Fad diets tend to take certain healthy messages to the extreme. Problems start when physiology is taken out of context, new dietary rules are extrapolated from poor science, or somebody just wants to make money off a new supplement or diet plan.
The Paleo diet claims to mimic our hunter-gatherer ancestors, promoting vegetables, fruit, meat, nuts and seeds while cutting out cereals and dairy products. The majority of people do however have the enzymes that digest the excluded food groups, which suggests we have evolved to eat them. Restricting a wide range of readily available, nutrient-rich food does not encourage good nutrition in the long-term. Similarly, a gluten-free diet that eliminates wheat, barley and rye, unnecessarily eliminates a large number of fibre-rich and nutrient-dense foodstuffs. Unless you are a diagnosed coeliac, give this diet a miss.
Other fad diets strictly categorise common healthy food as ‘good’ or ‘bad.’ The Acid-Alkaline diet, which claims to control metabolic pH by helping your body maintain a slightly alkaline state, labels supposedly acid-forming3 cereals and animal products as ‘bad’ and supposedly alkaline-forming fruit and vegetables as ‘good’. The Raw Diet excludes anything that has been heated above ~45 degrees Celsius on the theory that cooking destroys nutrients4. Both theories are actually based on physiology, but have been oversimplified and stretched into a philosophy that is not at all backed by evidence.
Other diets to consider with a pinch of salt are those with strict rules and precise eating patterns such as the Whole30, Dukan and Zone diets. They can generally provide your nutrient requirements (possibly with some tweaking), but are tricky and time-consuming to follow, remove much of the pleasure from eating and are not maintainable in the long run.
The diets that depend…
While there is no single definition of a detox diet, based on a concept that is not even supported by science5, such diets generally involve cutting out processed and refined food (including sugar and sometimes cereals), red meat, dairy products, alcohol and caffeine while drinking plenty of water, tea and fresh juices. It will not be harmful for a few days but, again, consider the nutrient groups you might be missing. Following a similar principle, clean eating is less strict and more rounded than a detox, as it allows lean meat, whole grain cereals, and some dairy products.
Shakes and meal replacements are formulated to provide nutrients with less kilocalories than regular food. They can have a place in properly managed weight-loss diets but should still be used in combination with real food. Commercial plans like SlimFast can be expensive to maintain, but for busy people a liquid meal is always better than no meal. Juicing can be a great way to increase fruit and particularly vegetable intake as part of a balanced diet, but juices lack protein and fibre6 and are not a suitable or satisfying meal substitute.
Intermittent ‘fasting’ diets, such as the 5:2, reduce the caloric intake on certain days or at certain times of day. Since there is freedom around the types of food you can eat, the deal breaker for these diets is what you choose when you do eat. Such regulations and rules definitely do not work for everybody though.
It is important to remember that any diet can be taken too seriously and become restrictive – not to mention socially isolating! Fresh, whole food is a step in the right direction, but a food group check is essential for any long-term eating plans. Always seek professional advice from a registered dietitian if in doubt.