The BDA, founded in 1936, is the professional association and trade union for dietitians in Great Britain and Northern Ireland, comprising over 8,500 food and nutrition professionals.
They warn that there seems to have been a spike in recent years of people's fascination with food, health and fitness.
"With the New Year around the corner, the influx of even more weight loss blogs and social media feeds, diet books, nutrition 'experts' and celebrity-endorsed fitness DVDs on the market is inevitable," Sian Porter, consultant dietitian and spokesperson for the BDA, said.
"All these options can make it overwhelming for people wanting to live a healthier lifestyle or lose weight.
"In this situation, it is definitely worth considering whether someone is simply profiting on your dreams and rather than shedding the pounds, all you're going to lose is your hard-earned cash."
And so, to help you discern the good from the fad, the association has compiled the worst celebrity-backed diets they have come across in the run up to 2017:
1. Clean eating
Celebrity fans: Miranda Kerr and Jessica Alba are allegedly fans of this "diet", and the Hemsley sisters, Madeline Shaw and Deliciously Ella reportedly advocate variations on this style of eating.
What's it all about? The idea is to avoid all processed foods and eat only "clean" foods, by eliminating refined sugar, cooking from scratch, and choosing foods in their natural state.
However some extreme versions of clean eating will exclude gluten, grains, dairy, and even in some cases encourage a raw-food diet.
Experts' verdict: Leave the cleaning for your kitchen work surface, not your food!
Whilst it is beneficial to reduce refined sugar and limit processed food intake, the idea of foods being 'clean' and 'dirty' is concerning.
In some circumstances this way of thinking is a prelude to 'Orthorexia Nervosa' - an obsession with foods that the individual considers to be healthy, and elimination of any food that is deemed unhealthy.
In many cases, foods that are actually nutritionally beneficial are deemed as unhealthy such as those containing wholegrains, fruit and dairy, with no basis in scientific evidence.
Unless you have a medically diagnosed intolerance or allergy to these foods, there is no need to eliminate them and doing so could lead to deficiencies in your diet.
Moreover, often clean eating substitute products - such as coconut oil, and various syrups to sweeten foods - are as high in calories, no better nutritionally and more expensive too.
2. Diet pills*
Celebrity fans: Kim Kardashian and The Only Way Is Essex star, Sam Faier, have reportedly used diet pills to lose weight.
What's it all about? Many of these pills claim to keep fat from being absorbed by your body, or 'melt' fat. Others claim to suppress appetite or boost metabolism.
Experts' verdict: Warning: danger!
Diet pills should never be taken without first consulting your GP, pharmacist or dietitian. Even regulated weight loss medicines on prescription can have nasty side effects including diarrhea.
Alarmingly, there has been a rise in the number of diet pills for sale online.
These products are often unregulated and can contain substances not licensed for human consumption like pesticides and have proven to be fatal.
*Those not prescribed by a medical professional
3. Teatoxes
Celebrity fans: Nicki Minaj and Kylie Jenner's Instagram accounts feature these products and Britney Spears reportedly uses them.
What's it all about? Teatoxing is short for 'tea detoxing' - these tea products have varying claims from detoxing the body, improving skin, reducing bloating and losing weight.
Experts' verdict: Tea-toxic! These teas often contain extra caffeine in the form of guarana or yerba mate, diuretic ingredients such as dandelion and nettle and the laxative, senna, which is not safe to take for longer than a week without medical supervision.
They might create the impression of weight loss and detoxification but this is usually water-weight loss.
Any further weight loss would most likely be due to substituting these teas in the place of high calorie drinks or food or as part of fasting plan.
With the risk of the accompanying side effects such a diarrhoea, dehydration, electrolyte imbalance, gut damage and a lack of scientific evidence, go "tea-total" on teatoxing.
4. The 6:1 diet
Celebrity fans: Coldplay singer Chris Martin reportedly followed this 'diet', claiming that it made him more creative and improved his voice.
What's it all about? The 6:1 diet involves eating like you usually do for six days and then for one day a week, some followers of this diet completely fast, meaning they don't consume any food for 24 hours.
Experts' verdict: Hungry for attention or just plain hungry?
Completely fasting unless properly managed is likely to lead to a lack of concentration, tiredness and low mood, which isn't going to make you more productive.
There is no evidence that a diet like this would make you more creative either, and depending on your age, health and lifestyle, fasting could be dangerous.
If you want to go down the fasting route, it is important to choose an evidence-based plan and consult a medical professional to ensure that this is done in a healthy and safe way.
5. Green juices
Celebrity fans: Rosie Huntington-Whiteley, Blake Lively and Gwyneth Paltrow reportedly consume "green juices".
What's it all about? Another means of 'detoxing' and weight management, green juices are essentially juices or smoothies made up of various fruits, vegetables, powders etc. Fans claim benefits ranging from detoxing to rejuvenation and weight loss.
Experts' verdict: Juice-less! The body is perfectly capable of detoxing itself without the aid of these green liquid concoctions.
Adding a green juice to an unhealthy diet is never going to make up for poor choices when it comes to food.
In addition, people add in ingredients like nuts, coconut oil and whole avocados to their green breakfast juices too - meaning these juices can add up to as much as 400 kcal per glass.
If you are still eating your normal breakfast on top of this, you are more likely to gain weight from consuming more calories, rather than lose weight.
A green juice is not a magic fix! Keep your veg and fruit whole and limit juice/smoothies to 150ml per day.
Porter concludes: "We hear it all when it comes to the latest way to shed pounds from the good to the bad, and at times, even the down-right dangerous!
"It seems that as a nation we are constantly on the search for that magic bullet approach to losing weight, wanting a quick fix, taking things on face value and trusting anyone when it comes to nutrition, food and diet.
"The truth is, if something sounds too good to be true, it probably is. Ask for evidence and get your advice from someone properly qualified and regulated with nothing to sell or promote.
"Make small sustainable changes you need to make forever. An eating pattern for life should be the one you can stick to in the long term, not a quick fix.
"Enjoy a rich variety of foods in appropriate portion sizes - moderation is key as well as being physically active. Losing weight is challenging and keeping it off is too, but it's not impossible.
"Don't make it even harder for yourself by following a fad."
