Your body is an extension of your energy system.   Thus what comes,
or doesn't come, into your body affects your energy system.
This means that it is possible for a malnourished and/or toxic body to
negatively affect your spiritual evolvement, not just your physical health.

All individuals that rely only on fruitarian or vegan diets are nutritionally
depleted. No buts or ifs.   While there may be extreme health conditions
necessitating the use of one of these diets, that doesn't change the truth
that fruitarians and vegans are nutritionally depleted.

It is very likely, almost certain, that vegetarians are nutritionally depleted, as well.

Omnivores, that is people that include meat in their diet, are the most likely
to have a balanced diet.   Of course, for good health the meat needs to come
from naturally raised animals (free of chemicals; daylight; free movement;
cared for by positive individuals).

Some people object to animal-based diets, especially meat, because to them
it feels wrong to hurt animals.
The body/energy system needs to be supplied with the nutrients that it needs
for optimal health.   This includes protein, heme iron, and energy.   Failing to do
so can hurt the individual's spiritual evolvement.
Depriving the body of needed nutrients contributes to poor health, possible
energy system fragmentation, and lack of energy.   Not only this affects the
person on many levels, but it also affects other people, possibly even the whole
world.   We are not separate islands; we all are interconnected energies.

To regard life as Holy and Sacred doesn't preclude killing animals for needed food.
However, contributing to suffering is not harmonious with love (even when the suffering
is your own).   Quickly killing an animal for needed food is congruent with the Divine,
but keeping an animal in inhuman conditions is not congruent with the Divine.
With quick killing there is no suffering - the animal's body goes into a state of shock,
so there is no pain and the spiritual energy of the animal leaves it.   This actually
goes for all life-forms, including fruits and grains.

If or how much meat and what kind of meat your body/energy system needs
can be reliably revealed by Neuro-Emotional Technique (NET).
The importance of this technique, the impact of the revelations (answers)
that come through it, cannot be overstated.   The list of NET practitioners (doctors)
can be found on netmindbody.com.   Even if one had to travel a considerable distance
to see such a doctor, it would be worth it.   (NET uses Applied Kinesiology, and has the big
advantage that NET doctors are trained to detect blocked or switched energy system
and can correct it = reliable answers.)

Of course, just because someone includes meat in his/her diet doesn't mean the person
automatically has all the required nutrients.   Some nutrients are difficult to get in the
needed quantities from normal food (plus cooking kills some nutrients), so supplementation
with high quality nutritional supplements may be needed.   Again, NET can help answer
what nutrients and how much.   Doctors of Naturopathy can also help.