On YouTube, a morbidly obese 22-year-old man named Robert has posted a desperate plea for help with weight loss.

"This is my last chance, my last hope," Robert says, his voice shaking with emotion. "I'm really scared that I'm not going to be able to watch my niece and my nephew grow up, and I'm not going to get to have a family of my own.

"My birthday's tomorrow. I turn 23, and I've never had a life. ... I'm asking for somebody's help. That's all I can really say. I'm speaking from the heart."

Robert, who says he weighs "between 600 and 700 or more pounds," tearfully explains that he's tried losing weight on his own -- he's even been hospitalized as a result of his extreme heaviness -- but the weight always comes right back. He hopes the video will catch the eye of someone who can help him.

he video has now been viewed nearly one million times, and among those who've seen it and want to help is TODAY's nutritionist, Joy Bauer. She has three simple, straight-forward pieces of advice for Robert -- or for anyone else whose weight loss needs are so daunting that they don't even know where to start.

1. Start walking -- every day.

Even if it’s just to the end of your driveway and back. In the beginning, it’s not really about the distance or the calories burned -- it’s more about getting your body used to regular physical activity and feeling a sense of accomplishment. Every few days, try to increase your duration by a little bit (even if it’s only an extra minute). Gradually getting into a regular walking routine can help boost your mood and fuel your motivation to get healthy and make better food choices.

2. Cut your portions in half.

If you’re not ready for a diet overhaul, start by cutting portions of whatever you’re currently eating in half. You’ll instantly reduce your calorie, fat and sugar intake by 50 percent -- and that’s substantial. Instead of six pieces of pizza at lunch, eat 3. Instead of 4 cups of pasta at dinner, eat 2. Then, as the weight starts to come off, you can start to focus on eating better foods.

3. Wipe out liquid calories.

Cut out all sugary beverages—whether it’s soda, lemonade, sweet tea, or fruit juice. You can literally save yourself hundreds if not thousands of calories per day. And, since liquid calories don’t fill you up the same way solid food does, nixing the sugary drinks won’t even leave you feeling hungry (you’ll hardly miss them). Sip on water, unsweetened tea and coffee, and naturally flavored seltzer instead