Caffeine

Cocoa beans are removed from their shells, fermented, dried, and liquefied as part of the chocolate-making process. Chocolate contains a small amount of caffeine, as well as other substances that may help elevate mood or energy in some people.
Commercially prepared chocolate products also contain added ingredients, such as sugar, vanilla, and lecithin.
The darker the chocolate, the higher the caffeine content
When cocoa beans are liquefied, the resulting liquid contains cocoa butter and cocoa solids. Both are used to make chocolate, although the amounts differ based upon the type of chocolate. Caffeine is found in cocoa solids, but not in cocoa butter.
You can usually determine the amount of caffeine in chocolate by how dark it is. The darker the chocolate, the more cocoa solids it contains. This increases the amount of caffeine it has per ounce. Since white chocolate contains only cocoa butter and no cocoa solids, it has zero caffeine.
 Dark chocolate contains 12 milligrams of caffeine per ounce.
Milk chocolate contains 9 milligrams of caffeine per 1.55 ounces.
White chocolate contains zero caffeine.
https://www.healthline.com/health/does-chocolate-have-caffeine#2

Effects of All Caffeine Drinks—The action of coffee and many other popular drinks is similar. The first effect is exhilarating. The nerves of the stomach are excited; these convey irritation to the brain, and this in turn is aroused to impart increased action to the heart, and short-lived energy to the entire system. Fatigue is forgotten; the strength seems to be increased. The intellect is aroused, the imagination becomes more vivid.—The Ministry of Healing, 326.

By this continual course of indulgence of appetite the natural vigor of the constitution becomes gradually and imperceptibly impaired. If we would preserve a healthy action of all the powers of the system, nature must not be forced to unnatural action. Nature will stand at her post of duty, and do her work wisely and efficiently, if the false props that have been brought in to take the place of nature are expelled.—The Review and Herald, April 19, 1887.

Cause of Time Lost on Account of Sickness—Many who have accustomed themselves to the use of stimulating drinks, suffer from headache and nervous prostration, and lose much time on account of sickness. They imagine they cannot live without the stimulus, and are ignorant of its effects upon health. What makes it the more dangerous is, that its evil effects are so often attributed to other causes.—Christian Temperance and Bible Hygiene, 35.

Habit-Forming Beverages—Tea and coffee are neither wholesome nor necessary. They are of no use as far as the health of the body is concerned. But practice in the use of these things becomes habit.—Manuscript 86, 1897.

An Unnatural Craving Produced—The continued use of these nerve irritants is followed by headache, wakefulness, palpitation of the heart, indigestion, trembling, and many other evils; for they wear away the life forces. Tired nerves need rest and quiet instead of stimulation and overwork. Nature needs time to recuperate her exhausted energies. When her forces are goaded on by the use of stimulants, more will be accomplished for a time; but as the system becomes debilitated by their constant use, it gradually becomes more difficult to rouse the energies to the desired point. The demand for stimulants becomes more difficult to control, until the will is overborne, and there seems to be no power to deny the unnatural craving. Stronger and still stronger stimulants are called for, until exhausted nature can no longer respond.—The Ministry of Healing, 326, 327.

Preparing the System for Disease—It is these hurtful stimulants that are surely undermining the constitution and preparing the system for acute diseases, by impairing Nature's fine machinery and battering down her fortifications erected against disease and premature decay.—Testimonies for the Church 1:548, 549.

The Whole System Suffers—Through the use of stimulants, the whole system suffers. The nerves are unbalanced, the liver is morbid in its action, the quality and circulation of the blood are affected, and the skin becomes inactive and sallow. The mind, too, is injured. The immediate influence of these stimulants is to excite the brain to undue activity, only to leave it weaker and less capable of exertion. The aftereffect is prostration, not only mental and physical, but moral. As a result we see nervous men and women, of unsound judgment and unbalanced mind. They often manifest a hasty, impatient, accusing spirit, viewing the faults of others as through a magnifying glass, and utterly unable to discern their own defects.—Christian Temperance and Bible Hygiene, 35, 36.

The Tongue Is Loosened—When these tea and coffee users meet together for social entertainment, the effects of their pernicious habit are manifest. All partake freely of the favorite beverages, and as the stimulating influence is felt, their tongues are loosened, and they begin the wicked work of talking against others. Their words are not few or well chosen. The tidbits of gossip are passed around, too often the poison of scandal as well. These thoughtless gossipers forget that they have a witness. An unseen Watcher is writing their words in the books of heaven. All these unkind criticisms, these exaggerated reports, these envious feelings, expressed under the excitement of the cup of tea, Jesus registers as against Himself. “Inasmuch as ye have done it unto one of the least of these My brethren, ye have done it unto Me.”—Christian Temperance and Bible Hygiene, 36.

An Economic Waste—The money expended for tea and coffee is worse than wasted. They do the user only harm, and that continually.—Christian Temperance and Bible Hygiene, 35.

Destructive Narcotics—All should bear a clear testimony against tea and coffee, never using them. They are narcotics, injurious alike to the brain and to the other organs of the body.—Counsels on Diet and Foods, 430.

Destroys Temple of God—The drunkard sells his reason for a cup of poison. Satan takes control of his reason, affections, conscience. Such a man is destroying the temple of God. Tea drinking helps to do this same work. Yet how many there are who place these destroying agencies on their tables, thereby quenching the divine attributes.—Manuscript 130, 1899.

Use Inimical to Spiritual Life—Tea and coffee drinking is a sin, an injurious indulgence, which, like other evils, injures the soul. These darling idols create an excitement, a morbid action of the nervous system.—Counsels on Diet and Foods, 425.

Those who indulge a perverted appetite, do it to the injury of health and intellect. They cannot appreciate the value of spiritual things. Their sensibilities are blunted, and sin does not appear very sinful, and truth is not regarded of greater value than earthly treasure.—Spiritual Gifts 4a:129.

Less Susceptible to Holy Spirit's Influence—To a user of stimulants, everything seems insipid without the darling indulgence. This deadens the natural sensibilities of both body and mind, and renders him less susceptible to the influence of the Holy Spirit. In the absence of the usual stimulant, he has a hungering of body and soul, not for righteousness, not for holiness, not for God's presence, but for his cherished idol. In the indulgence of hurtful lusts, professed Christians are daily enfeebling their powers, making it impossible to glorify God.—The Sanctified Life, 25.

Fosters Desire for Stronger Stimulants—By the use of tea and coffee an appetite is formed for tobacco, and this encourages the appetite for liquors.—Testimonies for the Church 3:563.

Some Have Backslidden—Some have backslidden and tampered with tea and coffee. Those who break the laws of health will become blinded in their minds and break the law of God.—The Review and Herald, October 21, 1884.

God's People Must Overcome—Those who have received instruction regarding the evils of the use of flesh foods, tea and coffee, and rich and unhealthful food preparations, and who are determined to make a covenant with God by sacrifice, will not continue to indulge their appetite for food that they know to be unhealthful. God demands that the appetites be cleansed, and that self-denial be practiced in regard to those things which are not good. This is a work that will have to be done before His people can stand before Him a perfected people.—Testimonies for the Church 9:153, 154.

Determined Perseverance Will Bring Victory—Those who use these slow poisons, like the tobacco user, think they cannot live without them, because they feel so very bad when they do not have these idols.

Why they suffer when they discontinue the use of these stimulants, is because they have been breaking down nature in her work of preserving the entire system in harmony and in health. They will be troubled with dizziness, headache, numbness, nervousness, and irritability. They feel as though they should go all to pieces, and some have not courage to persevere in abstaining from them till abused nature recovers, but again resort to the use of the same hurtful things. They do not give nature time to recover the injury they have done her, but for present relief return to these hurtful indulgences. Nature is continually growing weaker, and less capable of recovering. But if they will be determined in their efforts to persevere and overcome, abused nature will soon again rally, and perform her work wisely and well without these stimulants.—Spiritual Gifts 4a:128, 129.

In some cases it is as difficult to break up this tea and coffee habit as it is for the inebriate to discontinue the use of liquor.—Counsels on Health, 442.

A Pledge Embracing Tea and Coffee—All these nerve irritants are wearing away the life forces; and the restlessness, the impatience, the mental feebleness caused by shattered nerves, become a warring element, ever working against spiritual progress. Shall Christians bring their appetite under the control of reason, or will they continue its indulgence because they feel so “let down” without it, like the drunkard without his stimulant? Shall not those who advocate temperance reform awake in regard to these injurious things also? And shall not the pledge embrace coffee and tea as hurtful stimulants?—Counsels on Health, 442.

Some Need to Take This Step—We hope to carry our brethren and sisters up to a still higher standard to sign the pledge to abstain from Java coffee and the herb that comes from China. We see that there are some who need to take this step in reform.—The Review and Herald, April 19, 1887.

Proper Course at the Tables of Others—a Word to Colporteur Evangelists—If you sit at their table, eat temperately, and only of food that will not confuse the mind. Keep yourself from all intemperance. Be yourself an object lesson, illustrating right principles. If they offer you tea to drink, tell them in simple words its injurious effect on the system.—Manuscript 23, 1890.

Following Jesus in the Path of Reform—Jesus overcame on the point of appetite, and so may we. Let us move on, then, step by step, advancing in reform until all our habits shall be in accordance with the laws of life and health. The Redeemer of the world in the wilderness of temptation fought the battle upon the point of appetite in our behalf. As our surety He overcame, thus making it possible for man to overcome in His name. “To him that overcometh will I grant to sit with Me in My throne, even as I also overcame, and am set down with My Father in His throne.”—The Review and Herald, April 19, 1887.
https://m.egwwritings.org/en/book/110.401?hl=caffeine&ss=eyJ0b3RhbCI6MjUsInBhcmFtcyI6eyJxdWVyeSI6ImNhZmZlaW5lIiwidHlwZSI6ImJhc2ljIiwibGFuZyI6ImVuIiwibGltaXQiOjIwfSwiaW5kZXgiOjB9#415
Caffeine, a major culprit in tea and coffee, is easily available in many popular drinks (cola drinks) and over-the-counter medications. Physiological effects of caffeine are apparent in adults at doses of only 100-200 mg.—the equivalent of one to three cups of coffee. But for a child (age 1-5) one can of caffeinated soda is equal to four cups of coffee!

The Adventist Health Study found that the use of even one cup of coffee daily was associated with a 33 percent increase in the risk of fatal heart disease in men. Adventists who use two or more cups of coffee daily are reported to have a greater risk of fatal colon and bladder cancer. 

The caffeine syndrome is recognized by aggressiveness, hyperactivity, and sometimes psychotic behavior. Caffeine and the excess ingestion of xanthine alkaloids (found in coffee, tea, cocoa, and some popular beverages) affect people differently, usually observed in the abnormal stimulation of the nervous system and the inflammation of the gastrointestinal tract. 
Caffeine affects spirituality. Ellen White may not have known that she was many decades ahead of scientific confirmation when she warned that “all such stimulants and narcotics as tea, coffee, tobacco, alcohol, and morphine ... exert a pernicious influence upon moral character. The earlier these hurtful habits are formed, the more firmly will they hold their victim in slavery to lust, and the more certainly will they lower the standard of spirituality.”  But this truth is reflected in current studies. Researchers, among other findings, note that as coffee drinkers grow older, their coffee consumption increases. On a spiritual plane, this increase in consumption accompanies a decrease in religious involvement. 

Faulty diet and poor scholarship. In 1884 Ellen White stated that “nine tenths of the wickedness among the children of today is caused by intemperance in eating and drinking.” Six years later she wrote that “the diet materially affects the mind and disposition.”  Today widespread evidence indicates that there is a correlation between poor diet habits and poor scholarship. Better-fed children get better grades in school. When students with poor grades and poor diets are given nutritionally enriched meals, their grades and other scholastic indicators improve. 
https://m.egwwritings.org/en/book/656.2976?hl=caffeine&ss=eyJ0b3RhbCI6MjUsInBhcmFtcyI6eyJxdWVyeSI6ImNhZmZlaW5lIiwidHlwZSI6ImJhc2ljIiwibGFuZyI6ImVuIiwibGltaXQiOiIyMCJ9LCJpbmRleCI6M30%3D#3009