Annabel investigates…. 

The different fad diets and what actually works…


As you scroll up and down social media, news outlets and the internet, the next best diet seems to have come to light. Do you really know what all the diets consist of, are you wondering which one would work for you?

Today, Annabel and the Longevity Exercise Physiology teams at Drummoyne, EdgecliffMarrickvilleBella VistaRandwick, PymbleBalmain and Neutral Bay  discuss thoughts on the common fad diets with a Sydney based Sports Dietitian, and whether they really work, and why fad diets come and go so often.


Have you ever heard of the Vegetarian Diet, the 5:2 diet, or the Paleo Diet? These are just a few diets which have come into the spotlight over the past couple of years very briefly. If fad diets are followed in the right way, with the right advice from a Dietitian, these diets can work effectively. Let’s delve into the more common fad diets out there currently.


To begin with let’s explain what a fad weight loss diet is. A fad diet is any diet that promises fast weight loss without a scientific basis. These diets often eliminate entire food groups and as a result do not provide a wide range of important nutrients. Fad diets may provide short-term results, but they are difficult to sustain and can cause serious health problems. The best approach to weight loss is to follow a long-term, balanced eating plan and to exercise regularly.


(Nadolsky, 2022)


The Keto Diet

Firstly, we discuss the Ketogenic diet, informally known as the Keto diet. Surprisingly, the Keto diet is not a new diet, it has been used in clinical settings for a while to treat many conditions. This specific diet requires individuals to lower their carbohydrate intake to extremely low levels. The aim of this diet is for ketosis, or the burning of fat is enabled and therefore your body can break down your fat stores and allow you to use this as fuel for energy. By replacing carbohydrates with fat within the diet, you tend to see a lot of foods including avocados, butter, eggs, and cream included within the keto diet. This diet profile includes 10% carbohydrates, 70-80% fats, and only 15-20% from protein.


“A common misconception with this diet, is that individuals who only focus on decreasing carbohydrate levels, are not accurately sticking to this diet. Achieving the accurate levels and ratios of fat, carbohydrates and protein is essential to precisely complete the Keto diet.”


If you can follow these ratios accurately, this diet can be very effective. Fair quality evidence has also demonstrated that, in general, the greater the decrease in carbohydrate intake, the greater the decrease in fibre intake. Although, it should be noted that not all lower carbohydrate diets had inadequate fibre and not all higher carbohydrate diets necessarily met fibre recommendations (Schenker, 2001).

The Paleo Diet

The paleo diet has become more common over the last couple of years, with more individuals choosing to stick to this form of diet. This style of dietary intake is vastly different to the keto diet, as it includes more fruits and starchy vegetab

les such as sweet potato. Like the keto diet, reducing carbohydrates is critical but rather than the low ratio of 10% carbohydrates seen in the Keto diet, the Paleo diet requires carbohydrate intake of approximately 20-30%. The focus on fresh, unpro

cessed food naturally supports weight loss, as does the complete avoidance of processed carbohydrates. The only downside tends to be an especially low intake of dietary calcium and while fibre intake from vegetables and fruit may be adequate,  people find the lack of insoluble fibre intake from grains and legumes can result in constipation. There is fair evidence that following a Paleo diet can result in short-term (up to 18 months) weight loss in individuals with obesity, as compared to a Mediterranean-like diet, a diabetic diet, or a low fat/high fibre diet (Paleolithic Diet Summary of Recommendations and Evidence, 2015).

The 5:2 Diet

The 5:2 diet, is considered a fasting diet. This specific diet requires individuals to commit to two very low calorie, less than 500 calories per day each week. It appears that significantly restricting calorie intake for brief periods has multiple metabolic benefits in the body which in turn, supports fat metabolism. The biggest issue is that you will not lose weight as quickly as many desire to. There are no restrictions on the types of food you can eat, however a balanced diet is emphasised. The 5:2 and similar intermittent-fasting diets are said to be easier to follow than traditional calorie restriction, and an advantage is that you do not have to exclude any food groups (Fisher, 2022).


Always ensure that before commencing any diet, get advice and support from an Accredited Practicing Dietitian, who has a special interest in this area. Accredited Practicing Dietitian’s can work with you to make sure you meet your individual nutrition needs.


If you are looking for a recommendation for a Dietitian or to begin an exercise program, give Longevity Exercise Physiology Edgecliff, Pymble, Marrickville, Randwick, Drummoyne, Balmain, Bella Vista, and Neutral Bay a call on 1300 964 002 to book in a session today!


Written by Annabel Bergman


Fisher, R. (2022). What is the 5:2 diet?. BBC Good Food

(2015). Paleolithic Diet Summary of Recommendations and Evidence [Ebook].

Schenker, S. (2001). The truth about fad diets. BMJ323(Suppl S3), 0109318. doi: 10.1136/sbmj.0109318

Nadolsky, K. (2022). Fad Diets Explained. Retrieved 24 February 2022, from