Whole Wheat is supposed to be high fiber good for constipation but wheat produces lot of heat. How come?

I have always heard that wheat produces lot of heat hence should be avoided during summer coz it may aggravate piles , constipation etc But its also mentioned that Whole wheat has lot of fiber and hence is good for constipation. How come?

The health benefits of wheat depend entirely on the form in which you eat it. If you select 100% whole wheat products, however, the bran and the germ of the wheat will remain in your meals, and the health benefits will be impressive! Our food ranking qualified whole wheat (in its original non-enriched form) as a very good source of dietary fiber and manganese, and as a good source of magnesium.

The many benefits of whole wheat products are being recognized more and more by consumers.

Women Who Eat Whole Grains Weigh Less
Whole Grains Reduce Risk of Metabolic Syndrome
Whole Grains Substantially Lower Type 2 Diabetes Risk
Whole Wheat's Betaine Lessens Chronic Inflammation
Whole Grains Help Prevent Gallstones
Whole Wheat Gets You Going
Whole Wheat Promotes Women's Health and Gastrointestinal Health
Cereal and Fruit Fiber Protective against Postmenopausal Breast Cancer
There are number of other benefits too.
Here what type of heat ,do you mean ? In short it does not cause any adverse heat, but do produces heat to maintain basic functions of life .
And what is means by How come?.