Headaches are normal for the first few days of Phase 2 on the diet as the body adjusts to the low calorie diet. It is also normal during phase 1 loading due to the extra intake of sugars. While on P2 it is okay to take aspirin for headaches and other pains.
If you are drinking large amounts of caffeinated beverages (coffee and tea), then be sure to also drink a good amount of water or cut back on the caffeine to avoid dehydration which can cause headaches. If you take an aspirin be sure to use one that has little or no caffeine.
On the other hand you may be experiencing a headache because your body is craving caffeine. If you normally drink two cups of coffee but today you skipped them and now have a headache, they try drinking a cup or taking an aspirin that has caffeine.
Many people find that drinking chamomile tea helps keep off headaches and it is best to drink it at the first signs of a headache.
Additional ways to fight off headaches include taking a warm bath or shower or enjoying a relaxing nap.
Visit the WebMD Headache Center for more information on headache prevention and remedies.