OK so you've been to the gym...

An extension of the supplement market that's going mad right now. With the advent of HIIT workouts and strength training, it appears we're just not packing in enough protein. 

Enter shelves full of flavoured powders that promise everything from muscle maintenance to better energy levels. Go to a fancy studio and you'll even be able to pick out your protein-filled smoothie before your session so it's ready and waiting for you on your way out. 

However whilst they taste delicious and you can't argue the amount of protein they provide, are they really necessary, and do they have side effects like? We asked nutritionist, Libby Limon to weigh in on the protein powder debate...

Why do you think we've become so obsessed with protein powders?

I think that we have become more aware of the importance of protein in the diet in general. However, this should translate to the importance of a balanced diet, which includes all the important parts that create a healthy diet. Protein is one part, but also complex carbs, healthy fats and micro-nutrients. As well as the fitness side of protein in terms of muscle recovery, these in combination at every meal help us balance blood sugar, make us feel fuller for longer and therefore not overeat. Protein powders are an easy way to make something like a smoothie into a balanced meal. 

Can you still include them in your day if you don't work out?

Absolutely, they are not something that should be relied on for anyone. Variety is a key part of a healthy diet. However, once a day, they are great quick fix of the protein element to a meal. Particularly helpful for those switching to a vegan or vegetarian diet as another source of protein. 

Are vegan protein powders better than non-vegan varieties?

Vegan proteins come from plant sources, so often have a lower level of protein concentrated in them. On the plus side they are from more environmentally sustainable sources and a plant rich diet is one that we know is the most supportive of health and wellbeing. It is good to use a blend of different plant proteins to get the widest range of amino acids to support protein production in the body. 

Will they actually improve how we work out or the results we get?

The part of fitness that people often take for granted is the recovery. The quicker the muscle recovers, the more quickly you can return to your next work out and be able to train harder and longer. Nutrition during that recovery period can make a real difference on how the muscles rebound and therefore the overall results. This is where protein powders can help the process. 

Most claim to be low sugar but are so sweet with flavours like chocolate chip cookie, salted caramel and cinnamon bun, are we being fooled?

I would be wary of anything that is overly flavoured or sweetened. Sweeteners and artificial flavours can be more damaging then sugar. Choose a powder that is as natural as possible and avoid those with any long list of weird sounding ingredients. 

Is it true that they can cause constipation and bloating?

Protein takes longer to digest than carbs or fats so if you are having too much or your gut flora is out of balance it can cause fermentation which results in gas and gastro symptoms. (Also whey protein is made from milk so if you're lactose intolerant this can cause issues). 

Should anyone avoid them?

If you have a history of kidney problems, a high protein diet should be avoided. 

Aside from physical benefits, do they do anything else?

Absolutely, protein is really helpful for blood sugar balance which in turn can have major benefits in terms of sleep, stress, female hormone balance, weight management and overall mood. If you like them, they can be a quick and easy way to balance out your diet, although as with anything variety and moderation are key as well as choosing a high quality natural product. 

Want to know what's in our kitchen cupboards right now? Read on for our favourite five...

Link Nutrition, Vegain Protein in Chocolate Fudge, £19.95, linknutrition.com

NO1JRISH Vegan Protein Powder in Salted Caramel, £24.99, no1foodprep.com

Motion Nutrition Fresh Blueberry Morning and Chocolate spice Evening Protein Powders, £24.99 each, motionnutrition.com

The Nue Co Milk Protein + Gut Food, £50, net-a-porter.com

Form Nutrition Protein Powders, £26, formnutrition.com