Typically you would prorate it. That means if 1525 kcal (or Calories) is 61% of 2500 kcal you simply multiply everything by .61. However, there are a couple things to consider:
- The amount of protein you need to consume to protect your muscles doesn't change.
- The body needs at least 21g of Fibre a day to stay "regular" (i.e. no constipation)
In the other question you had, you figured out that you need about 65g of protein. Keep that number. I would also maintain the amount of Fibre they suggest. I personally need around 30g to stay regular.
Now, a nice little tidbit about carbs and fibre:
On nutritional labels, fibre is usually lumped in with other carbs. However, your body can't absorb the calories in the fibre so they really don't count. The concept of "net carbs" basically means subtracting out the fibre from the total carbs in the meal. If your English muffin (as we call them in the states) has 10g of fibre and 24g of carbs per muffin, the net impact on your body is only 14g of carbs. Just be careful with some of the "Atkins" labeled net carbs, as they also subtract out sugar alcohols which your body can absorb. Only subtract fibre.
Everything else, I would multiply by 61%. That would make it look like this:
Calories 1525 kcal
Protein 65 g
Carbohydrate 183 g (no more than)
Sugars 73 g
Fat 58 g (no more than)
Saturates 18 g
Fibre 24 g
Salt 3.5 g
NOTE: I personally think the sodium number for the GDA is a bit high (for the USDA the recommended allowance is around 2.5 g to 3 g of sodium). I tend to swell up when I have that much.