Day 035 - 12 Oct 94 - Page 49
1 requires, a series of events occurs which consumes a fair
2 number of those calories. The metabolism is increased,
3 the brain increases its secretion of a hormone called
4 noradrenaline or norapinephrine, thyroid which elaborates
5 a hormone called t-3 (which can just be written as t-3, if
6 you like), that hormone is more readily activated by a
7 high complex carbohydrate diet and, more readily
8 inactivated to another hormone called reverse t-3 when
9 carbohydrate has been displaced by another macro nutrient
10 such as fat.
11
12 The result of all this is that a high-fat diet has a
13 dramatic effect on the production of adipose tissue,
14 completely aside from whatever calories it may hold.
15
16 In addition to that, however, fat that is in the diet,
17 whether it is from an animal source or a vegetable source,
18 can be added to body fat with the loss of only, perhaps,
19 two or three per cent of its calorie content.
20
21 For carbohydrate, that is not possible. When the high-fat
22 diet is modified and the fat intake is dramatically
23 lowered and carbohydrate is substituted, storage as fat is
24 reduced. Carbohydrates, we do not have little drawers or
25 hooks for carbohydrate on our thighs or belly, so the
26 carbohydrate molecule has to be biologically disassembled
27 and a fat molecule made out of its constituents. That
28 process consumes about 23 per cent of its calories.
29
30 So, it is not correct to say, in spite of the fact that
31 I know some authorities have asserted that fat is
32 fattening simply because it is extremely dense in calories
33 -- it is; it has two-and-a-quarter times the calorie
34 content of carbohydrate or of protein.
35
36 But that is only the beginning of problem with fat as
37 regards adiposity. The effect on metabolism or, I should
38 say, the lack of effect of fat and the pronounced effect
39 of carbohydrate, and the ease with which dietary fat goes
40 nearly unmodified into the body's fat stores in comparison
41 with carbohydrate, which is unable to do that without
42 losing nearly a quarter of its calorie content, those are
43 very significant factors. I hope that is responsive to
44 the question.
45
46 Q. So, you would not agree then, as I think I have understood
47 what you tell us, that the effects of dietary fat on
48 hormone metabolism are uncertain?
49 A. That the effects of -----
50
51 Q. Of dietary fat on hormone metabolism are uncertain?
52 A. There is a great deal more that could be said than
53 what I have just gone into so far. I have only scratched
54 the surface. There is a substantial literature (which I
55 will not bore you with unless you are interested) on how
56 fat affects sex hormone binding globulin which holds
57 oestrogen and prevents it from being biologically active.
58
59 When different dietary groups are studied, one is
60 interested not only in levels of estradiol oesterone or
