Aside from the obvious neurological reasons, consider these factors:
Are your mothers teeth in good shape?  If she wears dentures are they a good
fit?  Discomfort from either case may cause her to change her eating
preferences.  If she cannot adequately express this to you you'll have to
watch carefully.  Also, as you may have read here, I lost my friend very
recently to dysphasia, the loss of control of muscles in the throat.  If you
suspect she needs "small bites", and it sounds like softer foods, you may
look into having an examination by a speech therapist...they are the ones
who can discover if there is a problem.  Especially if she seems to be
coughing when eating.

Dennis

Hi Sparky,

We had something like the same experience with my mother in law, who also
developed a "sweet tooth" and suddenly didn't want to eat meat anymore.
There were many foods she formerly loved and she would sometimes just not
want them, so it got that I just never knew what on earth to cook for her
anymore.

We found that the best way to get a balanced meal into her was to make lots
of very good thick homemade soups.   I would make a big pot of soup and
freeze the portions, so there was always a variety to choose from.
Eventually it became almost the only thing she really enjoyed eating.   You
absolutely could not fool her with soup from a can, either!!!

There are others who post here, and maybe they will have other, better
suggestions, but for us the homemade soups worked out to be the best
solution.

Now that she is in a nursing home, she is doing well for the circumstances,
and she does eat pretty well there.   I think there is something about
getting all the little containers on her tray that she likes.

Weight loss is a very common occurance with AD -  from loss of
appetite and from difficulties eating - and obviously, a person who is
not eating well becomes very vunerable to all kinds of health issues,
and ends up with no reserves should even minor illness strike. It is
as though they no longer realize they need to eat to live - and they
often don't seem to be hungry, despite loosing so much weight.

Many people with dementias also have perceptual problems, and thus are
easily distracted. My MIL had to take her meals on the ward, sitting
alone at a card table, since the bustle of a dining hall was too much
for her. Colour and patterns were also confusing to her - so she did
best of all at a plain table with no patterns on cloth or china, and
only one thing on the plate at a time. She needed coaxing, lots of
time, and a very relaxed atmosphere. She also had trouble with
utensils, so simple and fewer is better. In the last few years of her
life, she did much better eating with her fingers (knives and forks
were beyond her, and even a spoon became iffy). It was very messy, but
the important part was getting as much into her as possible. We did a
lot of hand feeding as well in the later part of the illness, since
even though she would stop eating a meal on her own and just sit there
as though she was done, she would open her mouth if you came at her
with a spoonful of pudding.

Have you tried feeding her lots of small meals and snacks instead of
fewer large ones? You might be able to get more calories into her that
way over the course of the day. I'd also try to make every bite count
in terms of high calory, high nutrient foods. Let her eat anything you
think will tempt her, even if its wierd and wonderful like rice
pudding for breakfast or cheesecake midmorning. Put lots of butter on
her food. Make her milkshakes or egg nogs. Use cereal cream instead of
milk. Try out some of those high calorie supplement drinks like Boost
or Gain (you can buy them at most pharmacies) instead of a mid
afternoon cup of coffee and a biscuit. Give her puddings.

You might also want to contemplate giving her softer textured foods -
the fact that she likes
yam so much suggests to me that the mushy texture may be easier for
her to handle. Many people with AD develop problems with chewing and
swallowing fairly early in the game, even if this isn't apparent to
you - it is related to coordination problems. They have trouble
manipulating things in their mouths, and mixed textures can be a real
problem (i.e. they do better with oatmeal porridge than with
cornflakes with milk, since the combination of a liquid and a crunchy
solid can be difficult). Even thin liquids can be a problem for
swallowing. Often they do better with thicker liquids, and they
actually sell products to thicken ordinary liquids like milk or juice.

Good luck with this.

Mary G.

Hey, even the oldest inhabitants here were once virgins like you.

More of the same - and some entirely new problems!

Just a thought for the future - try any of the 'complete food drinks'
such as Ensure.   They're sweetish and nourishing and also come
thickened as puddings.
They come in cheaper versions sold as own-brand in bigger pharmacies.

Your posting was fine.

Others have warned of chewing or swallowing problems behind your Mom's
change in habits.

I'd add that you must think like a detective, always looking for the
*real* reason for any change, since she will become less and less able
to tell you what's really wrong.
Of course, often there won't be any 'real reason' - it'll just be
yet another side effect of AD.  
But don't forget that people with AD can and do get all the other
diseases...

I think that doctors dealing with AD should have to spend a couple
of years as veterinarians, so they can get used to doing diagnosis
with zero input from the patient!