Followers of the Hare Krishna movement have the following restrictions on lifestyle habits:

"These so-called sense gratificatory acts are a sign of degradation below the human level. The scriptures therefore advise four regulative principles to keep us on the human level. They directly counteract the four pillars of sinful life and uplift us to the stage from which we can approach spiritual life."

The Four Pillars of Sinful Life

1) No Meat-eating

"To many people being a vegetarian means being a fruitcake, but reality shows that meat-eating has caused global problems that make one wonder whether those who favor it should not be considered nuts. For instance, research and comparative studies over the past twenty-five years show that a meat-based diet is the number one cause of heart disease and cancer. More than 25 billion animals and a much bigger amount of aquatics are mercilessly slaughtered for food yearly -- hardly a claim of civilized humanity. It makes us merciless and devoid of compassion for all that lives, humans included. "

Hare Krishnas are non-violent, and they see every living creature as a spiritual being, not to be harmed. And in doing so, it disturbs the karmic cycle. In other words, Instant Karma's gonna get you

2) No Illicit Sex

"We seem to have liberated ourselves from the foolish and primitive shackles of sexual restraint. Yet serious problems have caught up with our progressive march toward newer and stranger sexual practices. A plague of sexually transmitted disease claims ever-increasing victims. Most prominent and difficult to handle, is AIDS. Now an estimated 12 million adults and 1 million infants are infected and the expectations for the year 2000 are an estimated total of 30-40 million. So far a steady 40% of the cases have proven fatal..... Why this nightmare? Why can't we just enjoy a full and healthy sex life? Perhaps we have the wrong idea about the purpose of sex. Sex is meant for having children -- the natural result of sexual union. But we try to avoid nature's arrangement with contraceptives and abortions and thus spoil society. Then if nature tries to tell us that unrestricted sexuality is unnatural, we complain or blame a merciless God. The idea is not to give up sex altogether but to follow its real purpose...... Therefore we don't find unwanted children, abortion or contraception in ISKCON. We only indulge in sex within marriage, and then only to have children that will be raised in Krishna consciousness. By following the original purpose of sex, nature does not retaliate."

Hare Krishnas only have sex to procreate. They believe having sex for pleasure is wrong and distracts us from what really matters: God.

3) No Intoxication

"Intoxication refers to taking into the body substances that are not required for bodily sustenance and have altering effects on the mind and body. Vedic scriptures therefore include as intoxication everything from tea, coffee and tobacco to liquor, heroin and other more powerful drugs..... Such habits have destructive results. Besides the huge cost and resultant crime, addiction and loss of bodily and mental health eventually ends in disease, premature aging, and the inability to fix the mind intelligently and steadily on any subject or problem. Thus such habits impede spiritual advancement. Beyond this, the use of stronger and stronger intoxicants gradually destroy austerity and cleanliness, which the living conditions of drug-dependent persons confirm....."

Again, the philosophy here is that material things distract from the divine. One fixed in God consciousness stays high forever.

4) No Gambling

"Five thousand years ago, when the personality of Kali asked Maharaja Pariksit to designate where he could live, the King gave Kali four places -- places of gambling, drinking, prostitution and meat-eating. Where there is gambling, the other prominent symptoms of this age of quarrel and hypocrisy automatically appear. They used to open treatment centers for heroin addicts, now they open them for the compulsive gamblers. Compulsive gamblers run into enormous financial difficulties -- borrowing or even stealing from others. Heavy debt is a constant factor of their lives. They sleep poorly, usually drink a lot, and are tense, irritable, and indifferent toward eating and affection. They often think of suicide, but always think of the next bet... Any gambler thinks that with his manipulative ways he can get rich and enjoy. But certain laws defy these dreams, like the laws of nature, which are controlled by the Supreme Lord. These laws are not subject to gambling."

Again, drawing away from the divine.

For more on Hare Krishna/ISKCON, check above nodes.

All Quotes were taken from http://www.isckon.org