No matter where you look, you can't escape fad diets.
But a leading nutritionists warn following the trends encouraged by bloggers may seriously put your long-term health at risk.
London-based Rob Hobson says cutting out milk and dairy makes adults likely to have fragile bones as they grow older, reports Daily Mail.
While those desperate to get beach-body ready may also be making themselves vulnerable to colds as they avoid nutrients by cutting calories.
Here, in a MailOnline exclusive, Healthspan's head of nutrition reveals the dangers linked to various fad diets.
Stop cutting out milk and dairy
Last week a report from the Food Standard Agency (FSA) revealed that almost half of 16-24 year olds believed they had an adverse reaction to milk.
Cutting out milk and dairy is a recommendation in several popular diets including clean-eating, paleo, veganism.
And of course, it's also a no-no for the growing number of people who believe they have an allergy to milk.
The problem is that milk and dairy products are an important source of several key nutrients.
Cutting out on the foods reduces the intake of calcium and iodine - raising the risk of deficiencies.
It can also increase the risk of serious health problems like osteoporosis later in life.
One in two British women and a fifth of men over the age of 50 in the UK will break a bone as a result of osteoporosis.
Our bones continue to grow until we reach our mid thirty and during this time it's important to make sure diets contain enough calcium.
This help bones grow denser and stronger which reduces the risk of osteoporosis later in the life.
Unfortunately the National Diet and Nutrition Survey (NDNS) found a large number of young people are failing to get enough calcium in their diets to meet their needs.
Dairy products are also a useful source of iodine - a micronutrient important for women during pregnancy and young children that contributes to growth and brain development.
The NDNS found 22 per cent of girls aged 11-18 and 10 per cent of adult women in the UK don't get enough iodine in their diet.
Don't cut down on calories
It's not just fad diets which increase the risk of nutritional deficiencies.
With summer just around the corner, there's no shortage of diets that promise to be able to get you in shape for your holiday.
But restricting calories intake to shift those pounds that crept on over the winter months means cutting back on the amount of food you eat.
And this usually means you are also restricting the number of vitamins and minerals that you consume.
Some foods, such as oily fish, are high in calories, which means they are not usually included in weight-loss diets.
But they provide important nutrients like omega-3 fatty acids and vitamin D, which can be hard to get from other foods.
Analysis of these popular diets show the nutrients most likely to be lacking in are omega-3, vitamin D, vitamin A, iodine, riboflavin, calcium, iron, zinc and selenium.
As well as increasing the risk of long term health problems, nutritional deficiencies can have more immediate effects.
These include compromising the immune system, leaving you more vulnerable to colds and other infections.
Lack of iron in the diet is one of the most common cause of low energy levels, and can even cause problems like hair loss.
It's vitally important when you are on any sort of restrictive diet that you focus on what nutritionists called "nutrient dense" foods.
Of course, supplements should never be used as substitute for a healthy balanced diet. But they can work as an insurance policy to ensure you're not missing out.
Diets likely to be nutritionally weak
Low calorie diet/low fat diets
can be short on vitamin D, calcium, iodine, fats soluble vitamins A,D,E,K - omega 3 fats
Clean-eating diets often involves cutting out dairy and gluten and while they appear very healthy they can be deficient in whole host of nutrients including calcium, B vitamins, iron, iodine
Low sugar/low carb diets could be short on vitamin C, potassium, B vitamins, fibre
Alkaline/PH diets are often short on calcium, iron, zinc, iodine
Low carb diets can be low in fibre and deplete levels of friendly 'probiotic' bacteria are important for a healthy digestive system