Before ordering bottled water, coffee or diet soda at a restaurant, ask yourself first: “Do I really need it?— Because since you are living in America, chances are that quenching your thirst does not have to cost anything. In most cases, you can drink tap water — for free.

In the meantime, 27,000 children, mostly in Africa, are dying every day for not having enough to eat, according to the World Bank. About 1.4 billion people are living in extreme poverty, getting a daily income of only $1.25 or less, way less than what you would pay for a Starbucks latte. So consider this for one moment: Every drink you skip buying could save lives.

That essentially is the message philosopher Peter Singer wants to convey in his new book, “The Life You Can Save: Acting Now to End World Poverty,— which hits the shelves today.

Named by Time magazine as one of “The 100 Most Influential People in the World,— Singer is a bioethics professor at the Princeton University Center for Human Values and author of the groundbreaking “Animal Liberation.—

“The Life You Can Save— is the product of Singer’s 30 years of work on how to respond to hunger and poverty.

“I hope this book will persuade you that there is something deeply askew with our widely accepted views about what it is to live a good life,— he writes. “This book represents my effort to distill what I’ve learned about why we give, or don’t give and what we should do about it.—

In fewer than 180 pages, Singer tries to achieve two goals: challenge us to think about our “obligations to those trapped in extreme poverty— and persuade us to help.

To achieve that, Singer said, he used “ethical arguments, provocative thought experiments, illuminating examples and case studies of charitable giving to show that our current response to world poverty is not only insufficient but ethically indefensible.—

The book resonated with me: I am from the Philippines, a Third World country where 40 percent of the population lives on one meal a day. When I moved here in 2007, I was shocked by how much material wealth people have accumulated.

“When we spend our surplus on concerts or fashionable shoes, on fine dining and good wines, or on holidays in faraway lands, we are doing something wrong,— Singer writes. In his book, Singer argues that instead of paying for unnecessary things, if people would channel their money to organizations effectively fighting extreme poverty, the problem could be solved.

Singer proposes that Americans earning more than $100,000 annually should donate 5 percent of their salary. “I believe that doing so would be a first step toward restoring the ethical importance of giving as an essential component of a well-lived life,— he writes.

In an e-mail, Singer said he gives away one-third of his income, mostly to Oxfam America and GiveWell.net. “So I give more than the standard I set in my book for people of my income,— he said.

But what about today’s economic situation, with many Americans losing their jobs, homes and health care? A situation like this makes it difficult for people to donate money to charity.

Singer argued that even though the U.S. is suffering from economic depression, “we are still, compared to the poor, extraordinarily well-off.—

Singer pointed out that the amount of foreign aid the U.S. gives is “totally insignificant in comparison to what we spend on as a nation and in comparison to what our government spends.—

The government spends about $22 billion a year on foreign aid, and Americans privately put in about another $10 billion, for a total of $32 billion. Compared with the $787 billion stimulus package signed by President Barack Obama last month, “that’s trivial,— Singer said.

As he tries to attract potential donors, Singer also attacks the penchant of people for ostentation. His book discloses names of extravagant billionaires who could be doing more good with their money. And his message to them is: “Instead of having to spend money to keep up appearances because otherwise people will think you can’t afford to buy new clothes or a new car, or to renovate your home, you now have a good reason for keeping the things that you find perfectly comfortable and serviceable: You have a better use for the money. And you could even end up happier, because taking part in a collective effort to help the world’s poorest people would give your life greater meaning and fulfillment,— he writes.

Singer also points to how wealthy nations such as the U.S. are harming poor countries by using goods made from raw materials obtained from unethical dealings from resource-rich but otherwise poor nations.

Singer said lawmakers on Capitol Hill could address this by focusing attention on the problem. “Make a speech about it, and to move that a committee investigate which U.S. and other corporations are buying oil, minerals and other resources from dictators who obviously are not putting the money received into helping the people of their country,— he said.

In persuading us to rethink the way we spend our money, Singer presents the scenario of seeing a child drowning in a fountain on your way to work.

“If you don’t wade in and pull him out, he seems likely to drown. Wading in is easy and safe, but you will ruin the new shoes you bought only a few days ago, and get your suit wet and muddy. By the time you hand the child over to someone responsible for him, and change your clothes, you’ll be late for work. What should you do?—

Chances are, Singer said, you would save the child. And if you don’t mind ruining your shoes and suit in the process, then giving to charity to save the lives of children in Africa should not be any different.

So why are we not giving? Singer explains that there is an amount of selfishness that is relevant. “Many people think most don’t do anything so why should I? If you could break people out of this vicious cycle then everyone would do it,— Singer writes.

Singer says in his book that we don’t have to act drastically. Just a moderate amount will help. “The ultimate purpose of this book is to reduce extreme poverty, not to make you feel guilty,— he writes.