I agree with Natalianyx that caloric balance is the cornerstone of weight-loss and maintaining a healthy weight. But I think there is probably a bit more nuance to the issue, especially in terms of maintaining health and energy levels. Some attention to macro-nutrient balance is probably going to be useful for most people. For vegans there are some additional issues related to how to obtain sufficient quantities of certain nutrients.
It's really not difficult to get sufficient calories on an inclusive vegan diet, by this I mean not eating any animal products, but eating a range of foods, including vegetables, fruits, legumes, nuts, whole grains, and yes, even moderate amounts of oil and other processed vegan foods, as well as, the occasional treat. If you're having trouble getting enough calories on a vegan diet, increased intake of nuts, avocados, beans, whole grains and/or fruit should take care of that.
For tracking calories, macro-nutrients, and other values, I like the website myfitnesspal.com . It's free, has listings for lots of foods, and has a nice user-interface. You can also access it via an ap on your phone. It's easy enough to log calories by hand, but logging calories, fat, protein, etc. gets to be a little tedious.
Note that a lot of Morningstar Farm's products are vegetarian, but not vegan, as they contain eggs and/or milk. Pretty much all fake meat is considered processed. I guess you could make an argument for unflavored seitan being not-terribly processed, but anything Morningstar/Gardein/Bocca/etc. certainly counts as "processed food." However, the labels are not going to say that, if anything they're going to portray the foods as "natural."
As far as what kinds of bread or anything else is vegan, read the label, if the product contains meat of any kind, eggs, dairy, gelatine, or honey it's not vegan. Meat-derivatives can be kinda hard to spot, since it can be included with "other flavors." Milk/dairy, eggs, fish, and shellfish are all easy to spot as foods that contain these must be clearly labeled because they are common allergens. There are also some food additives (dough conditioners, flavorings, etc) that are not vegan, some people exclude those, some don't. Note that a lot of the healthiest vegan foods will not be marked vegan, for example, produce, dried or plain canned beans, and whole grains. For things like canned beans I recommend checking labels just to be sure, but for the most part, single or few ingredient items are going to be kinda obvious.
