This is a very interesting question and something that's a very common problem for many people. Sweating is one way your body discharges excess waste and rebalances itself. If you put too much junk in your body or too many things that are not used up, they need to get out of your body.You say that you never used to stink! I can believe that. Many people don't for parts of their life and do for others. Those people who smell foul most of the time, either have bad hygiene or they are eating the wrong foods for their type of body. In other words, their body is not able to dispose of the foods as efficiently as the next person.
Look at your hygiene first. What you may consider hygienic may not necessarily be hygienic!
- Don't wear the same clothes two days in a row.
- Wash every day.
- Use a deodorant.
- Reduce your stress levels.
- Drink lots of water every day.
On the foods side, a high protein is not good if you have a problem with sweating. In particular, I advise staying away from red meat. Eat red meat no more than once a week, and then in moderation.
I would also strongly recommend that you keep well away from culinary herbs and spices in your diet. They are also notorious for smell!
The better your hygiene and diet, the less chances that your sweat will smell. In fact, I cal almost guarantee you that if you washed every day (assuming that you don't!) and ate a wholesome vegetarian diet with lots of water daily, your problem would disappear in as little as 3 days.