On a 7-day cruise, everybody gains weight. I mean everybody.

Here's my diary from that sailing, port by port. Six nights in, this table told me everything.

Unlimited pasta, bread, wine, cheese and dessert, 24 hours a day. The buffet never closes and room service runs until midnight. By the end of the week, nobody is holding back.

You can see it on their faces when they walk off. The puffiness, the bloat, the look that says “I'll deal with it when I get home.” I see it every single sailing, because I'm the one watching them walk on and walk off.

What I learned: almost everyone leaves heavier and puffier than they came. That's why the one table that didn't drove me so crazy.

The Greek and Italian women ate the most and looked the best

There was one group I could never figure out. They traveled together, they were loud, they were laughing, and they ate more than anyone on the ship. Usually in their 50s, sometimes their 60s.

Loading their plates at breakfast. The full pasta course at dinner, plus the bread basket, plus the wine. Dessert, and not sharing it. Every night for seven nights.

Then they walked off the ship looking better than when they boarded:

• Glowing skin, even after a week of late nights
• Light on their feet at the gangway
• No stretchy pants bought at port, no “I'll deal with it at home”

Meanwhile, everyone else was swollen and stuffing their suitcases.

What I learned: eating the same food didn't give everyone the same week. Some bodies handled it far better.

Eating less didn't fix what I was feeling

Here's the part I never told anyone: I was the one gaining weight. For years I told myself it was genetics. Mediterranean genes. Lucky women. That's what I said to feel better while I hid my belly behind my staff uniform.

Because I'd watch them eat twice what I ate, and I was the one who felt heavy. I tried all of it:

Every sailing, different women, same result. And I kept feeling heavier after every meal, however small.

What I learned: when you feel bloated and heavy on a salad, the amount of food probably isn't the whole story.

Three women, one small bag, two softgels each

Then, on the last night at sea, I saw it happen. I was clearing tables. A woman, maybe 57 or 58 and gorgeous, sat with her girlfriends. The whole table was wrecked: plates everywhere, three bottles of wine deep.

She opened her purse, pulled out a small bag, popped two little softgels and put it away. One of her friends did the same. Then the third. Same bag, right there at the table, like the most normal thing in the world.

I couldn't help it. I walked over. “I'm so sorry, I have to ask. What did you just take?”

“Sweetheart, sit down. You want to know why we all look like this.”

Her friend pulled out a chair for me. These women are not shy. Then she looked at me the way your auntie does when she knows something you don't:

“How long has your stomach been like that?”

I was standing there in my uniform, getting called out by a woman who had just eaten enough pasta for a family of four. But she wasn't being mean. She wanted to help.

What I learned: they weren't skipping meals. They had a small daily habit, and they did it without a second thought.

She said the real question is what happens to your food after you eat it

“That's not fat, my love. Your gut is out of balance, and it gets to your food before you do. The crew food and your age have little to do with it.”

Her version was a lot more colorful, and some of it was village wisdom rather than science. So when I got home, I looked up the part I could check. The basic idea holds up.

That was me after every crew meal. And it explained why women who looked after their gut every day could enjoy a week of pasta and still walk off feeling good.

Millions of women blame the bread, their age or their willpower. Very few think about the gut that has to handle the food.

What I learned: I'd spent years counting what went on my plate and zero time on what happened after it.

Their secret was two old-world oils from their side of the sea

She held up the bag. “Two oils. Oregano and black seed oil. This is our oregano, sweetheart. It grows on our hills. Our grandmothers used it, our mothers used it, every woman in my village uses it.”

She was fussy about one thing. “Not the cheap oregano they sell everywhere.” Most oregano softgels don't say how much carvacrol is inside, and most leave out black seed oil completely.

Her friend leaned over: “We've been trying to tell you people for years. You just won't listen.” The whole table watched me write the name down on a cocktail napkin.

Those women had a habit their mothers taught them, so I started one too

Two softgels every morning before my shift. Here's how my first month went. Everyone's body is different, so read this as one person's diary, not a promise.

I laughed and told her nothing happened. Then I ordered her a bag too.