If you increased the amount of protein in your diet, and around the same time noticed constipation showing up, what is the fix in this case?
First
It matters that your protein intake is not so high that it crowds out the rest of your nutrient needs. Generally, protein should not make up more than 35% of a person's daily calorie needs.
For example, if your calorie target for weight loss is 1500 calories and you allocate 30% of that to protein, that equals 450 calories (roughly 110 grams of protein). By the way, that ratio is considered good, even a bit on the high side.
Second
Most people who deal with constipation after increasing protein are missing something important, increasing their carb intake as well. Protein sources do not contain fiber, so it matters that your carb intake is adequate and good (fiber-rich, starchy carbs), because this gives waste enough bulk and ensures easy digestion and elimination.
Third
Alongside more fiber, it matters to drink enough water, because more fiber without enough water means constipation. So make sure to drink enough water for better digestion.
Fourth
The quality of the protein matters a lot. Protein powder, being a processed product with added sweeteners, can cause digestive issues for some people, which can in turn worsen constipation. If that applies to you, it is better to choose protein from natural sources.
Fifth
Because protein is more filling than other nutrients, eating too much of it can crowd out the rest of the nutrients you need, ones that matter just as much and help with easy elimination, such as fruit, vegetables, and whole grains.
Which brings us back to the first point: make sure the protein in your diet is at a good, suitable level, not too high, to avoid constipation.