My BMR is 3,300 calories and for weight loss, my daily allowance is 2,300.

Breakfast, lunch and snacks are running me about 1,300, leaving 1,000 calories for my dinner.

It's hard to quantify exactly what goes into my dinner meals (Mum cooks) but using Fit Day I've made a rough guesstimate that a typical meal consisting of two cups of cooked white rice, a half cup of tomato sauce and a cup each of sweetcorn and peas might run me about 842 calories, leaving me roughly 150 calories a day off my daily allowance, which itself is 1,000 calories less than BMR.

What are the consequences of falling short of my daily calories allowance?

FYI, here's my typical breakfast, lunch and snacks:

Breakfast: 2 biscuits of Weetabix in a shallow pool of low fat milk (188 calories)

Lunch: A brown bread sandwich filled with tuna, sweetcorn, peppers, onions and tomato and a Muellerice (876 calories)

Snack: 3-4 medium Granny Smith apples (240-320 calories)

My BMR is 3,300 calories and for weight loss, my daily allowance is 2,300.

Do you mean your maintenance is 3300?

Breakfast, lunch and snacks are running me about 1,300, leaving 1,000 calories for my dinner.

It's hard to quantify exactly what goes into my dinner meals (Mum cooks) but using Fit Day I've made a rough guesstimate that a typical meal consisting of two cups of cooked white rice, a half cup of tomato sauce and a cup each of sweetcorn and peas might run me about 842 calories, leaving me roughly 150 calories a day off my daily allowance, which itself is 1,000 calories less than BMR.

Leaving you with very little high quality protein in a crap load of calories. Not exactly what I'd consider an effective meal.

What are the consequences of falling short of my daily calories allowance?

What are your stats? Age, sex, height, weight?

Eating too little isn't so much a concern if you have a ton of weight to lose. It's more a problem with people who are relatively lean, trying to get leaner. But this isn't always the case.

I'm not so sure a 1000 calorie deficit below your maintenance (assuming by BMR you really mean maintenance) is the best option but that's a very general comment since we don't know much about you.

Yeah, by BMR I mean maintainence.

I am 23, male, stand at 5'11", too see me you'd say I have a muscular build and I weigh 96.1 kg (target is 78 kg)

And for good measure, I excercise for a minimum of 30 minutes, 5-6 days a week, moderately to intensively

Put it this way.

The more extreme the deficit, the more important nutrient quality matters. By this, for example, I mean the less calories you consume or the larger a deficit you find yourself in, the more critical it is to take in adequate amounts of things like protein.

Right, more protein, gotcha. S'pose a bit of meat with my rice and veg couldn't hurt. I generally tend to pass on the chicken because....well, I don't really like it, so don't see the point in ingesting the extra calories. But needs must and all that.

Put it this way.

The foundation of all diets geared toward weight loss and health should be built with protein.

Whenever I design a diet for myself or a client, I first set calories. After that, the very next step in ensuring adequate protein.

It's that important.

Might be wrong I guess but is there not a lot of protein in tuna? That's one of the reasons I started having tuna sandwiches for lunch every day instead of chicken! I'd say the tuna in my sandwiches generally come to 140-160g worth?

Yes there's a lot of protein in tuna.

And chicken.

Good sources of protein include chicken and turkey breast, fish, pork tenderloin, lean ground beef, top round steak, cottage cheese and other dairies, eggs, whey, etc.

Having balanced meals will take you a long way toward improving your nutrient composition. By balanced, I mean some protein, some carbs, and some fats.