Lee Suckling: The most controversial diets this year

Is watermelon okay as part of the paleo vegan diet? Photo / Thinkstock

There are lots of hot diets out there for 2015, and now we’re halfway through the year these seven persist to top the list. But, which of them are backed up by scientific evidence?

The Girlfriends Diet

One would think a diet made up by magazine editors would be dubious. However, the Girlfriends Diet is based on actual science. Created by Good Housekeeping magazine, this diet is basic Mediterranean (fish, greens, olive oil, a dash of red wine) but with a twist. Studies (such as one by the American Psychological Association) show that women have the best chance of loosing weight and keeping it off if they have "diet buddies", so The Girlfriends Diet advocates undertaking this simple Mediterranean diet with a group of friends, for maximum encouragement and eventual effect.

The Fasting Mimicking Diet (FMD)

The 5:2 diet - whereby you eat whatever you wanted five days a week, then limit your daily caloric intake to 500 calories for two consecutive days -was all the rage two years ago. This has evolved to the FMD, which switches the regime to five days of fasting and two cheat days. This diet was developed by scientists at the University of Southern California, and it is proven to aid in weight loss (but in a healthier way than other fasting diets). This is because the five-day stretch of calorie restriction has a specific composition of foods, the combination of which mimics fasting without making you feel deprived.

The Bulletproof Diet

This new diet consists of 50 to 60 per cent of daily intake from good fats, 20 per cent from protein, and the rest from vegetables. Basically, that makes it a new interpretation of the ever-controversial Atkins diet. But, there's a clincher: it also includes a daily "bulletproof" coffee, which is black coffee with butter in it. The Bulletproof Diet was created by a technology billionaire and has no science to back it up.

Pegan

Pegan is supposed to be a hybrid of Paleo and vegan - but it still allows animal protein... Confused? Here's the story. Pegan is a moderate diet for those who don't want to go extreme Paleo or full-blown vegan. Pegan combines the so-called best elements of Paleo (unrefined, whole foods and good sources of protein) with the plant-based philosophy of veganism. What you're left with is 75 per cent green things, 25 per cent protein. Though many nutritionists argue Pegan is healthy (in reality, it's just a basic clean eating plan) there's no science behind it.

Whole30

The idea of eating only "whole" foods, those as close to nature as possible, is backed up by studies such as those by Mayo Clinic and Food & Nutrition Research. In fact, you'd be hard-pressed to find a nutritionist out there who doesn't advocate whole, unprocessed foods. Whole30 is a basic elimination diet that involves 30 days of eating only whole foods. That means no booze and no chippies - in fact, pretty much nothing from a packet. The goal is to reset your gut health and give your body a chance to heal. If you break the diet, you have to start your 30 days all over again.

DASH

The DASH diet - (which stands for dietary approaches to stop hypertension) - aims to primarily fight off high blood pressure by emphasising whole foods (fruits and vegetables, meat, whole grains, and anything else unprocessed) and cutting out everything sugary, salty, processed, and artificial. There's lots of science behind DASH - according to studies published in Archives of Internal Medicine, Diabetes Care and Renal and Urology News, with long-term adherence the diet can be successful in lowering high blood pressure, risk of stroke, heart failure, and kidney stones. Not so much "controversial" but more an "unsexy" diet, which is why you likely haven't heard of it.

The Bespoke Diet

The more we look at fad diets, the more we realise some work for select people, but do nothing for others. Israeli scientists from the Personalised Nutrition Project argue this is because of our individual gut microbes. That is, a bespoke diet, tailored to your unique biological make-up is the best way to improve your health and aid in weight loss, these researchers say. Thanks to a computer algorithm that learns how your body responds to different foods, The Bespoke Diet will tell you which foods to take out of your diet (e.g. bread for the people who see glucose spikes after consumption). At present, only people in Israel can use the algorithm via an app on their phone, but watch the Personalised Nutrition Project's website for international developments.

• Lee Suckling has a master's degree specialising in personal-health reporting.

Join the conversation on the Herald Life Facebook page