Macronutrients are generally fat, protein, and carbohydrates. There are different types of each (for example, casein protein, saturated fat, monounsaturated fat and so on) but for this discussion we will assume you have already worked out those differences for your diet.
For fat loss, I recommend fats and fiber-rich foods first. Most low-sugar vegetables are great examples of fiber-rich foods. Then protein and lastly, although best avoided, any high-sugar foods.
The reason for these recommendations is that we want to keep insulin spikes as low as we can. Cauliflower will produce a very low spike in insulin, and is not anything dangerous to most. Healthy fats will also not produce large spikes.
Bear in mind, foods that combine fats and protein, as well as protein on its own, can lead to undesirable protein spikes. Whey protein, for example, may lead to a spike in some individuals. This may not be dangerous for most and in moderation, but ideally for weight loss, insulin spikes should be kept quite low. And exception may be after resistance workouts, when an insulin spike can help shuttle protein to muscles for repair.
For regular meals, however, the order would be fibrous foods, healthy fats, then healthy proteins. Sugars may follow if you must. Although, fruits may be acceptable last, in moderation. It seems common sense that blueberries (sugars and fiber) will produce a higher spike than, say, spinach (fibrous with less sugar.)
Thus, an example meal would be: Spinach and cauliflower medley (fibrous), followed by (or combined with) an avocado. Then chicken breast, lean meats, or salmon. Followed by a sensible portion of fruit, if it makes sense for your goals.
It is important to thoroughly chew food, as this will help digestion and appropriate insulin-spike preparation, when eating foods in a given order, with the aim of lessening any insulin spike.
Healthy fats and fiber have been shown to help blunt insulin spikes of other foods.
Please note, even if a food is low on the glycemic index, it may still raise insulin significantly. Beef is one example.