Rather than liking something new or getting into a habit immediately, more than seven in ten adults admit there is a 'bedding in' period before they finally settle in.
It also takes 23 days of dieting for it to become easier to stick to and six exercise classes to make it part of your everyday routine.
But on the flip side, it takes an average of 51 days to break a bad habit, such as smoking or eating chocolate.
And three quarters of adults admit they have a tendency to give up too easily.
Camilla Sheeley, from Tilda Basmati rice, which commissioned the research to launch its Live Big Hearted Urban Tri:Try said: "It can take a while before we really get in to something new, particularly if it's a new habit we need to build into our routine or one which may be difficult to stick with initially.
"But it's interesting to see just how long it takes to get into different things in our lives.
"While it may only take minutes to get into a new film or book, something which is hopefully going to lead to a healthier lifestyle such as going to the gym or eating healthily can take a little longer.
"However, it's encouraging to see that if you stick with it for just a matter of weeks, you'll soon be eating food which is good for you as part of your everyday routine."
The study, of 2,000 adults, found 71 per cent say it often takes them some time to get into something new such as a hobby or habit.
Because of this, the average adult needs to attend the gym seven times before it becomes part of their routine, starting to see the effects of a new exercise plan after just nine sessions.
It also emerged that it takes eight weeks to settle into a new job, while getting into the habit of having a regular lunch break at work takes eight days.
You also need to cook a recipe six times before you know it off by heart and spend six days cooking dinner at home to get out of the habit of grabbing a takeaway instead.
A creative hobby, such as knitting or painting, takes around 6 weeks to get into, while a new active hobby like cycling or swimming needs seven weeks before you settle in to it.
You also need to allow two episodes of a new TV series before you are sucked into the plotline but learning something new such as a language or instrument needs eight and a half weeks.
But almost eight in ten admit they find it difficult to stick with a new hobby or habit.
And 58 per cent reckon they would be more likely to succeed at something new, such as a healthy eating regime or going to the gym if they were doing it with someone else.
Researchers also found 56 per cent of people have quit a book before getting to the end, while another 65 per cent have stopped watching a film half way through because they weren't into it.
Others have given up on a diet or healthy eating regime before getting to the end or their goal (39%) and stopped going to the gym or exercise classes earlier than they intended (26%).
Almost 46 per cent of people even admitted they often start a new year, or new season with good intentions of sticking to a new habit or hobby but often end up giving up.
Tilda is inviting people to Tilda Tri:Try at Lumiere London on 6th, 7th or 8th June for an evening of HIIT (high intensity interval training), uplifting yoga and meditation and healthy refueling recipes designed to help people feel good and get into a healthy lifestyle, quicker.
Bradley Simmonds one of London's top personal trainers and Tilda advocate will be appearing at the Tilda Tri:Try added: "I'm a big fan of HIIT and when you get into it, it's easy to make it part of your daily routine. Try it this summer - you'll be surprised how quickly you get into it."
The time it takes to get into the habit of something:
Exercise classes - 6
Gym sessions - 7
Diet - 23 days
Healthy eating regime - 30 days
Having a regular lunch break at work - 8 days
Cooking for dinner instead of getting a takeaway - 6 days
Cooking a new meal or recipe before you know how to make it off by heart - 6 times
Eating lunch sitting down instead of on the go - 7 days
A new book - 21 pages
A new film - 13 minutes
Settle into a new job - 8 weeks
A new creative hobby such as knitting or painting - 6 weeks
A new active hobby such as cycling or rock climbing - 7 weeks
Episodes of a new TV series - 2
A new sport or physical activity - 6 weeks
Learning something new such as a musical instrument or language - 8 and a half weeks