Top 3 worst fad diets to avoid in 2018

With the start of the new year, many celebs and self-appointed nutrition ‘experts’ will be filling our screens, pages and social media feeds with their latest fads, products and programms – many promising more than they can possibly achieve.

To help you push back against this tide of misinformation, our dietitian has provided tips to help spot bad dietary advice as well as given her take on the top 3 fad diets to avoid in 2018.

The Alkaline diet

What is it? Supporters of this diet believe that by changing the foods they eat to consume more alkaline and less acidic foods, they will change the pH balance of the blood and reduce health risks. Worryingly some wrongly claim it can treat cancer and that incorrectly ‘acidic’ foods cause osteoporosis.

Dietitian Verdict: Unfortunately, this diet is based on a basic misunderstanding of human physiology. Whilst diet can change the pH value of urine, is not related to the pH of your blood, which cannot be affected by diet. The human body is perfectly capable of keeping its blood within a very specific pH range and if it fails to do so, you would become very ill, very quickly!

Bottom Line: You’ll most likely lose weight because you are cutting out processed foods and eating more healthily – nothing to do with the acid or alkali content of foods.

Pioppi diet

What is it? This is essentially a new spin on a low carb, high fat diet and is based very loosely on the diet of a small Italian village called Pioppi. The diet recommends a higher level of fat compared to the traditional Mediterranean one –with followers encouraged to eat lots of vegetables, nuts, legumes, and fish and avoid eating red meat, starchy carbs, and sweetened treats.

Dietitian Verdict: The book pays homage to eating plenty of fruit and vegetables, fish, olive oil, alcohol in moderation and not being sedentary (much like the current UK government guidelines). However, it strangely excludes traditional Italian carbohydrates such as pasta, rice and bread – but includes coconuts – perhaps because they have a low carb content. It also uses potentially dangerous expressions like “clean meat” and encourages people to starve themselves for 24 hours at a time every week.

Bottom line: The traditional Mediterranean diet is a healthy choice but this spin on it has many flaws. The only reason their other advice is likely to help people lose weight is because like any diet, it involves eating less food and calories.

Ketogenic diet

What is it? This diet is out there in many versions rather like Atkins or Paleo but the principles are the same: very low carb (around 20-50g per day or 5% total calories), high fat, moderate protein intake. Typically it excludes grains, dairy, legumes, soy, most fruits and starchy vegetables. The carbohydrates in the diet come mainly from small amounts of non-starchy vegetables, nuts and seeds.

If you significantly decrease the amount of carbohydrate in your diet, the body switches from primarily burning carbohydrates, to burning fat, for energy. This causes an increase in levels of ketones in our bodies. Supporters claim it can help you to lose weight, control hunger and improve your health. Worryingly some say it can treat or prevent a number of different types of cancer which is just not true.

Dietitian verdict: A dietitian-planned ketogenic diet can be a very effective treatment for people with epilepsy. For weight loss, the diet works like any other by cutting total calories and removing foods people tend to overeat. Initial side effects may include low energy levels, increased hunger, sleep problems, nausea, digestive discomfort, bad breath and poor exercise performance. It can be an effective method of weight loss in the short term but it is hard to sustain in the long term and most of the initial weight loss seen is often associated with water/fluid losses. Over-restricting any one food group (including carbohydrate) will also mean a poorer intake of vitamins, minerals and fibre in particular. The type of fat also needs to be considered to prevent an intake of high levels of saturated fat.

Bottom line:  Requires careful planning for balance of heart and gut health.

So how can you tell the dieting fact from the fiction?

Stay away from diets that…

  • Promise a magic bullet to solve your weight problem without having to change your lifestyle in any way
  • Promise rapid weight loss of more than 2lbs of body fat a week
  • Recommend magical fat-burning effects of foods (such as the grapefruit diet) or hidden ingredients in foods (the coffee diet)
  • Promote the limitation of a whole food group, such as dairy products or a staple food such as wheat (and suggests substituting them for expensive doses of vitamin and mineral supplements)
  • Promote eating mainly one type of food (e.g. cabbage soup, chocolate or eggs) or avoiding all cooked foods ( the raw food diet)
  • Recommend eating foods only in particular combinations based on your genetic type or blood group
  • Suggest that being overweight is related to a food allergy or a yeast infection
  • Recommend ‘detoxing’ or avoiding foods in certain combinations
  • Offer no supporting evidence apart from a celebrity with a personal success story
  • Are based on claims that we can survive without food or by having liquid meals only
  • Focus only on your appearance rather than on health benefits
  • Are selling you products or supplements
  • Recommended the same diet for everyone without accounting for specific needs

….Remember, if it sound too good to be true – it probably is!


Our dietetic service is led by Michelle Bremang & Christina Merryfield. For more information about appointments and further advice click here.

Date: 22/01/2018