Struggling to shed the pounds? These fad diets might help. Photo / Getty Images
Another day, another diet, or so it seems, in a world where diet headlines are guaranteed to draw the interest of plenty of eager readers.
Fad diets, or those that are wildly popular for relatively short periods of time, come and go.
The Cabbage Soup Diet, Israeli Army Diet and the Lemon Detox Diet are just a few that have held the limelight, albeit briefly, over the past few years.
What may surprise you, is that a number of these diets do actually work, even in the long term, if they are followed the right way.
So, here is the lowdown on some of the more effective popular diets of the moment.
Ketogenic diets are not new. Rather they have been used in medical settings to manage a range of clinical conditions for many years.
A keto approach requires followers to reduce their carbohydrate intake to an extremely low level so that ketosis, or fat burning, is induced as the body breaks down fat stores directly to be used as fuel.
A keto approach requires followers to replace carbohydrate intake with fat, so the overall diet profile features less than 10 per cent of energy from carbs, up to 70-80 per cent energy from fats and just 15-20 per cent of energy from protein.
This is why you see a lot of avocado, butter, eggs and cream used in keto diets.
The reality is that most diets that claim to be "keto" are actually just low in carbohydrates as opposed to achieving these ratios of fat, protein and carbohydrate.
In real life, achieving these ratios in your diet is somewhat challenging but if you can, and do follow it, it will work very effectively.
Unlike the keto approach, which requires strict carbohydrate restriction, the paleo diet includes fruit and some starchy vegetables, including sweet potato.
This results in a reduced carbohydrate intake, as opposed to the extremely low levels seen in keto dieting.
This macronutrient shift sees between 20-30 per cent of total your energy coming from carbohydrates.
The focus on fresh, unprocessed food naturally supports weight loss, as does the complete avoidance of processed carbohydrates.
The only down side to this diet tends to be an especially low intake of dietary calcium and, while fibre intake from vegetables and fruit may be adequate, a number of followers find the lack of insoluble fibre intake from grains and legumes can result in constipation.
The Very Low Calorie Diets generally uses meal replacement products and diet shakes to achieve an extremely low calorie intake of just 800 calories per day.
This approach has been used for many years, in clinical settings, to achieve weight loss.
Now, it is commonly used by weight loss surgeons prior to surgery.
VLCDs are extremely effective in reducing fat stores in the liver, while also inducing ketosis as the overall calorie and carbohydrate intake is extremely restrictive.
VLCD's work extremely effectively but the issue is that once they are ceased most if not all weight tends to be regained unless underlying eating habits are significantly altered long term.
Fasting diets, or specifically the fasting regimen that requires followers to commit to two very low calorie (less than 500cal) days each week, have been shown to be effective in supporting relatively slow (1-2kg a month) weight loss.
It appears that significantly restricting calorie intake for brief periods has a number of metabolic benefits for the body, which in turn, can support fat metabolism.
The biggest issue is that you will not lose weight as quickly as many desire.
The main difference between a low carb diet and keto diet is the proportion of protein the diet contains, with low carbohydrate diets still requiring less than 10-20 per cent of calories to come from carbohydrates.
This also leaves more room for dietary protein than strict keto diets do.
Low carbohydrate diets, or diets that require followers to eliminate virtually all bread, rice, cereal, pasta, fruit and starchy vegetables, are extremely effective at achieving fat metabolism, at least in the short term.
The issue for most is that as soon as any of these high carb foods are reintroduced, weight tends to be rapidly regained and becomes more and more difficult to lose in subsequent attempts.