Well, no, if your thyroid sucks, your metabolism won't be fine even with good exercise & a healthy diet. BTDT. But I do agree that improving metabolism is no magic bullet for digestion. ANd yes, cold is another hypothyroid sign. A major one. I recommend a Free T3 test right away in the case of constipation + feeling overcold. Thyroid Mistreatment, Hypothyroidism Scandals, and Thyroid Treatment Problems | Stop The Thyroid Madness. Those are classic symptoms.
5'4" 36yo mother to five sweeties & married to their AMAZING DaddyGrok
Starting: 185 lbs (March '10)
Current: 132.5 lbs
Goal: 135 lbs (Hit Jan '13)
Beating bingeing since 10/31/11 on my Leptin Reset journey
More fiber makes things much worse. At least it did for me. And I tried for a few years, resulting in having my gall-bladder removed.
I have chronic constipation, and I thought it was strange that more fiber seemed to make things worse--until my GI doctor confirmed that he personally has the same problem. He says that fiber has been 'oversold' based on flawed research.
I've yet to find a solution to my issue. The GI recommended Miralax, and it works for me, but I don't like the 'way' it works. But I've tried almost every other remedy suggested by anyone.