it’s normal and expected for a pregnant woman to gain weight to help support the caloric demands of a growing fetus, but I believe what you’re referring to is excessive weight gain from a junk-food filled processed food diet.
So the best place to start is with my VPF+C dietary principle which ensures that she’s getting all of the macronutrients needed. If you haven’t yet watched the “Food pillar” inside the Beginner’s Health Roadmap, that’s where I would start (video linked above).
In addition to those dietary guidelines, here is a list of nutrient-dense foods that will help guard against dietary deficiencies during pregnancy:
• Eggs
• Fish
• Leafy greens
• Full fat, organic grassfed milk products
• Nuts and seeds
• Organic organ meats
• Poultry
• Red meats
• Sea vegetables
• Whole grains
Hope this helps.