To Accumulate
To Get Piled Up
intransitive verb, godan verb
Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means accumulate and the verb version is to accumulate.
If something accumulates, you can start with one, but you need at least two (つ) things to say it has accumulated. If you don't, then there's nothing accumulating at all.
体重を減らすために、日常の食事の量を極端に減らす必要はないよ。それよりも、バランスの良い、健康な食事を取ることの方が重要だ。ちりも積もれば山となるって言うじゃないか。
You don’t have to drastically decrease the amount of food you normally eat to lose weight. It is more important to have a balanced, healthy diet. It’s said every little bit counts.