The media is full of the latest wacky diet or nutrition craze, many of which are endorsed by celebrities promising fast weight loss. Whether it’s ‘high fat low carb’, paleo, juice detox or ‘clean eating’ the choice is seemingly endless. To put it very simply, in order to lose weight, the energy (calories) you eat needs to be less than the energy you expend. Reducing energy intake and increasing the energy you use (through physical activity) will enable you to lose weight. How you do this and the diet you choose is the confusing part. This article has been written to give you the low-down on the pros and cons of popular diet crazes, and then give you some balanced information about the approach used by Slim & Save.

The low-down on common ‘faddy’ diets

High fat low carb

Whether it’s high fat low carb (HFLC) or high protein low carb, there are many variations of this type of approach. They involve a low carbohydrate intake, and increase the intake of fat or protein to compensate. Some restrict carbohydrate so much that it induces ‘ketosis’ – a state where the body breaks down fat into ‘ketones’ to provide energy, causing rapid weight loss.

Pros and cons: One perceived benefit it that people often lose weight very quickly initially, which can be motivating. Some diet plans can be very prescriptive, which some people may like. However, there are many negatives about these approaches, and they can be detrimental to health. The high intake of saturated fat (from sources like red meats, cream, cheese, butter and coconut oil) encouraged in the HFLC approaches may increase risk of heart disease. Some plans advise the addition of salt to foods and encourage salty processed meats like bacon and sausages, which is a concern for people with high blood pressure. Long term high protein intakes may also be dangerous for health, as they may increase risk of kidney damage and osteoporosis.

Does it work? Whilst rapid weight loss can seem motivating at the time, these diets are unhealthy and unsustainable in the long term. Upon returning to ‘normal eating’, most people put the weight back on. More research is needed into the long term health implications of following a high fat or high protein diet.

Intermittent fasting, e.g. 5:2, 4:3 and 6:1 diets

There are so many variations of this type of diet available; most require you to restrict calorie intake for a number of days a week, whilst eating ‘normally’ on the other days. They work on the assumption that if followed ‘correctly’, you will consume a deficit in calories each week, and therefore lose weight.

Pros & cons: Watching calorie intake on ‘fasting’ days helps you get a grasp of the calorie content of foods, helping you make more informed choices. However, the severe calorie restriction on fasting days may leave you exhausted and irritable, making this approach difficult to stick to – you’re then more likely to attack the cookie jar. There’s also a danger of overcompensating on non-fasting days; in fact, some label non-fasting days as ‘feast’ days, suggesting you can eat what you like! Fasting is not safe for everyone, such as diabetics on insulin or certain medications that could induce a hypo.

Does it work? Whilst research into this approach has shown some success in specific populations , there’s no evidence this can be translated into population recommendations. More research is needed into the best approach (e.g. 5:2 or alternative day fasting), optimum calorie intake on fasting days, and long term sustainability. Whilst some people succeed, the evidence so far suggests that it doesn’t work any better when compared to other weight loss techniques

Paleo

Again there are many variations available. These diets promote the consumption of only foods presumably available to our prehistoric ancestors, i.e. vegetables, fruit, nuts, roots and meat. These diets exclude dairy products, grains, salt, legumes and processed foods.

Pros & cons: Paleo diets emphasise the importance of fruits, vegetables, and healthy fats (like avocados and nuts), eating less sugar, salt and processed food which are good health messages. However there are lots of reasons why these diets can be unhealthy. These diets exclude whole food groups, leaving you at risk of nutrient deficiencies like calcium (as dairy foods are excluded). Beans and legumes are a great sources of fibre and protein, but these are also excluded. Butter and coconut oil (which are high in saturated fats) are promoted, despite the effect of saturated fats on cholesterol levels. The excess protein intake promoted by this approach can be unhealthy; not to mention the sustainability issues and environmental impact of increasing meat consumption. This diet is expensive and hard to sustain.

Does it work? The actual diet consumed by our Paleolithic ancestors if difficult to replicate today. Modern versions of the diet are likely to be based on fashion rather than actual science. Only a handful of studies have examined the effects of this approach. They all included small sample sizes and some didn’t even measure weight loss . Overall, research suggests this diet is difficult to stick to, and the long term effects of it are not yet known.

Juicing

Often advertised for ‘detoxing’ as well as weight loss, these short term diets consist entirely of fruit and vegetable juices. Juices can be made at home or bought pre-made from a company.

Pros & cons: These diets are not nutritionally balanced, missing out on important nutrients like calcium, protein, iron and zinc. Whilst most plans are short term, some people may be tempted to carry for longer than advised due to the quick results they may see, causing real potential for nutritional deficiencies to develop. Juicing even short term could be dangerous if you have certain pre-existing conditions like diabetes when fruits are juiced, it releases the sugar from the cells, which can significantly increase blood sugar levels. On the ‘plus side’, some people may discover new fruits and vegetables they’ve not tried before.

Does it work? There is no evidence to support any health benefits of juicing. Most juicing diets provide around 1000–1200kcal a day, so it’s not surprising to lose weight on a plan (simply due to creating a calorie deficit). Whilst quick weight loss may be experienced, this is probably more water and muscle loss than fat. Most people will regain this weight very quickly after the plan has ended.

Clean eating

These approaches involve eating foods that come in their purest unprocessed or raw form. This means avoiding processed foods, food additives, refined sugar, articificial sweeteners to name but a few. Instead the focus is on eating whole grains, proteins, fruit and vegetables (preferably organic).

Pros & cons: Whilst these diet plans may get you thinking a bit more about your food and where it comes from, it can take healthy eating a step too far towards the extreme, and even encourage extreme dieting behaviours. There’s also a real chance people may miss out on essential nutrients and fats without really careful planning.

Does it work? There is no evidence to support any health benefits or weight loss benefits of so called ‘clean eating’. Any weight loss benefits are simply down to eating less energy (calories).

So what’s different about Slim & Save’s approach?

Slim & Save promote the use of short term meal replacement plans to encourage quick but sensible weight loss results. You stop eating ‘normal’ food at some or all of your meals (depending on whether you’re on ‘lifestyle’ or ‘simplicity’), and have specially manufactured products instead. The overall calorie intake will be less than 800kcal per day. The products are nutritionally balanced (containing added vitamins and minerals), so it’s safer than many other diet approaches. Slim & Save’s programmes work by inducing ‘ketosis’ – a state where the body breaks down fat stores into ‘ketones’ to provide energy in the absence of carbohydrates (the body’s preferred energy source).

Slim & Save programmes provide comprehensive information about how to follow the plans, with online menu plans and support available from the expert team and fellow dieters through the forums. Whilst the programme can feel restrictive, particularly when it comes to family meals and eating socially, support is available to help you find idea and solutions for these occasions.

One of the biggest criticisms of meal replacement programmes, as with other approaches, is that without making healthy eating and lifestyle choices, it’s common to revert back to your ‘normal’ eating patterns again afterwards and put weight back on. With Slim & Save, however, there is support available from the team to encourage a more balanced diet and healthy lifestyle even after you’ve achieved your weight loss goal. This includes the options of following our weight maintenance plans, which have been written by a registered dietitian, receiving support through our weight maintenance forum and having your questions answered by the team.

Mark Smither's Two Year Maintenance

If you have not yet read Mark Smither's follow-up story we published earlier this month then be sure to read the entire story and see his amazing pictures here

Written by Annemarie Aburrow RD BSc (Hons) PGDip, Slim & Save Dietitian.