@RME
I'm pro anyone giving it a go but seriously, save your money, this really is a tough love reply from me, i think you have between Bob Hope and No Hope of you getting this off the ground and into a viable concern. Posters here have been very kind to you, i get that but its false hope IMO.
I have a lot of experience in the tech sector but put simply:- you will need capital and skills to get an APP and website built correctly and illustrate your USP to a decent standard - that's the easy bit. You will then need buckets of cash to market this to gain any decent traction, the route to market will be challenging and further I'm not convinced the market demand is there especially when it comes to someone handing over their hard earned to subscribe/ purchase from you depending on your model. The diet sector is saturated and you need to stand out from the others.
I know its not the reply you want, but lets say you raise some cash via family, friends, crowd etc, use EIS /SEIS and convince some backers and its enough seed capital to get your tech launched, get some proper stats and your marketing messages right and some early stage traction to prove concept. You will then need a much bigger raise for a series A raise early growth for a decent marketing budget and growth plans to hit this hard.
The market meanwhile is absolutely saturated with hungry mouths to feed all needing investment, check out pitching events for a flavour of that, you will see some amazing businesses struggling to get investment, you will see deals done at ridiculously low values and you will see M & A at low ball levels. My gut feeling is that this would struggle to secure/ wont get funding support - thats my view, sorry.
If despite my reply you still want to proceed, i would suggest you focus on gathering solid data, feedback from possible user groups and put a decent business plan together and make contact with a regional funder, find your regional VC :-
British Business Bank is a government-owned economic bank specialised in helping businesses in the UK access financial support. Find out more.
www.british-business-bank.co.uk
They will tell you what you need to demonstrate to have any chance of investment success - Even if you didn't go on to raise via a regional VC any other capital provider will want similar proof of concept information. In doing this step you will at least save yourself the initial seed capital and stress and heartache of building an APP and getting your message right only to find its wasted money spent if you cant then raise to scale.
Good luck to you anyhow, you sound like a really nice guy and i'm sure you can do well, just don't think this idea is the one that will do it for you. I really don't like trying to burst someone's bubble here, but equally would hate to see you chuck tens of thousands at this to find you cant take it further.