How to protect yourself if your boss prefers your colleague who underperforms and gives your work to your colleague so he can take the credit for it in front of others, and your boss blames his mistakes and your colleagues on you

I'm not sure there is much you can do to protect yourself in the situation you describe.

Make sure, however, that your perception that your colleague underperforms is an accurate one. It sounds as if the boss thinks that it YOU who is underperforming. See if you can get some honest, unbiased feedback about how you are performing.

Even if you are not performing up to a level of excellence, giving your work to someone else in front of everyone else is not a good management action, so it would seem that it is time for you to move on.

Can walking for exercise be made more effective by wearing ankle weights, carrying dumbbells, or wearing a weighted backpack? What are the downsides?

In simple physics, all these weights are lose and works only against the gravity i.e their weight will always be pointing towards the ground, anything done against is offering resistance, so with Ankle Weights, if you raise legs higher than usual when taking steps, will work on thigh muscles, carrying Dumbbells will work on the shoulders if you're not

Would you agree that in order to lose weight is better to try a combination of exercise and reduction of calories instead of just exercise or just reduction of calories?

Losing weight is determined by what you eat. Exercise alone is not enough to lose weight, but you can lose weight by changing what you eat to better choices, even without exercise.Having said that, exercise helps keep your muscles as you lose weight, and also helps you lose a little more.Exercise also has other benefits such