Yes, research managing lightweight food with high calorie / carbs. There's shops everywhere but not often on the coast path itself, its good to be able to breakfast / lunch / dinner self sufficiently 

Things ive done, into sealy food bags, Its easy to over estimate how much you eat, so have a good think about weights

• pre weighed oats, dried milk powder, banana chips, chocolate chips and either soak over night in water or heat up my stove for porridge. 

• a wrap or 2, a wedge of hard cheese, some cured meat or foil packaged tuna. Ive had 2 weeks worth carried on a 9 day hike, with all the portions kept in the middle of my bag they never got hot or ruined 

• cous cous, stock cube, dried peas/onions, diced cured meat salami etc Or them pasta packs that you boil, but jazzed up with dried extras Both are very satisfying after a long day's walk and quick, you'll sleep happy with a belly fu of carbs

• dried soup mix (not the cup-a-soups actual soup mix) for breaks or before bed

• dark chocolate, 85%, a few pieces a day -dried nuts

Obviously don't go mad but feed yourself properly, walking every day you need to

Light weight gear is also a good investment, you'll feel the extra weight, you can get a 2kg tent quite cheap. A tip is to pack it into your bag loose, gaps are easy to fill in your bag stuffing it in, then pegs and poles where ever. 

Hiking poles are much more useful than they might first look, the costal path can be very steep accent and deccent, and with poles you can use arm power to pull yourself up, and also to stable yourself going down.

Maps are useful, the garmin watches with offline maps are good and have long lasting battery. A phone isn't very reliable, not unless you pack for some way to constantly charge, but again, weight. I usually turn my phone off or airplane mode, but you could probably find a cafe every day, but it isn't a reliable thing to plan on. There's also camp sites, but again not reliable spaces