I would love to see a higher limit on sugar content in food, ideally not more than 15%, but a 40% is a start. What legal actions/procedures I can take as an individual to get something put in law to prevent food companies from putting higher levels of sugar in their products?
There are a few main things you can do:
Start a Petition
The government's e-petition website is a good place to start. As has been discussed previously on this site, these are rarely (or never) successful at directly affecting government policy. That does not, however, mean they are worthless as they can be useful to bring an idea into the public consciousness and make it more acceptable for people to talk about.
Contact your Representatives
In the UK, there are two useful points of contact for national issues like this. The first is your local MP. The second is the government department responsible for the policy area your point comes under (in this case The Department for Environment, Food and Rural Affairs) and the Minister in charge of it (here George Eustice).
There are three useful methods of contact:
This is the easiest way to get in contact, but also the least likely to affect change. Emails can sit unread for a long time, and generally are considered to least useful way to get in touch.
Physical letters are the classic way of getting in touch with representatives. They give a physical quantifier of public opinion on an issue, and many politicians have stated that they pay most attention to the size (and contents!) of their mailbag.
These are also a good way of letting the depth of your feeling be known. They are an inherently personal experience, and they demand an immediate response. They do, however, require you to invest a large amount of time.
Organise a Peaceful Protest
If you want to make a more direct statement on an issue, you can try to find like-minded people and protest. Holding a march or rally can raise the public profile of your cause. You do, of course, need a group of people who will come together (the internet can be useful here). You should also ensure that you are aware of any notifications you need to make to law enforcement or the local authority, and any specific laws govenring such activities in your area.
Organise Direct Action
If you feel that your issue demands more than simple assembly, you can come up with direct actions to take to promote your agenda. if this appeals, it is worth looking at organisations such as Greenpeace for inspiration. It should be noted that his may involve breaking laws, which you may or may not be comfortable with.
Run for Office
If you feel that none of your representatives are listening, and you cannot get the public momentum you need to change their minds, or cannot translate that momentum into action, consider running for political office on a platform including this issue. There is, after all, no way to ensure that your representative listens to you than being that representative!
You could try and find some activists, groups or NGOs that have the same vision of reducing the sugar content in food in general and contact them, perhaps help them in some way and become part of their organization/group.
Personally, you could probably create some sort of a lawsuit or petition, presumably with the help of a lawyer. The chance of achieving anything is however in this case very close to 0.
The last option from my point of view is to start some sort of activism yourself. You could perhaps create some organization/NGO or join politics that would represent your idea and help you market it. You need power/people/public reasoning and approval in order to be able and try to propose rapid changes such as this...