The fats we want our girls to eat come from whole foods that haven’t been altered by food processing plants. One good source? Avocado. (NADIA C.)

Adolescence is a critical time of life for nutritious eating — only during infancy does the body grow and develop more.

Think about a typical tween or teen girl. She is going through a growth spurt or two, her levels of physical and mental activity are high, and she’s either beginning or in the thick of puberty. Menstruation changes her iron needs, increased estrogen production can cause new food cravings, and her hormone development relies on certain nutrients. In other words, a lot of changes are transpiring, and I would argue that this girl’s choice of foods is vital.

Fat has become a bad word in our country, especially among girls. This commenced when I was a teen. We were trained that fat makes us fat, and we should avoid fat as if our lives depended upon it. But the opposite is true: A girl’s health depends on eating plenty of fats — but by this I mean good fats.

[Read: What I said when my daughter criticized her body ]

I don’t want to crush any hopes, but good fats are not found in bacon and potato chips. Sorry. And they are not trans fats, which are found in processed cakes and cookies made with shortening, chips made with hydrogenated oil, and most fried and fast foods. The fats we want our girls to eat come from whole foods that haven’t been altered by food processing plants.

Where can girls find these good fats?

• Raw nuts and seeds

• Fish, especially wild salmon, mackerel and sardines

• Avocadoes

• Olives

• Olive oil

• Flaxseed oil (ideal in salad dressings)

• Coconut oil (for roasting or in a smoothie)

• Grapeseed oil – great for sautees

• Walnut oil – ideal for baking

• Grass-fed butter

Healthful fats from these sources should make up 25 percent to 35 percent of your daily calorie intake. I am not saying that your daughter count fat grams or calories to reach that exact percentage; rather, she should grasp the big picture. A significant portion of the food she eats should contain healthful fats. Though you may have avoided them growing up, she should not.

Explain to your daughter that good fats will not make her fat. Instead, they are essential for brain health, mood stabilization and proper hormone development. And they are a concentrated source of sustained energy — energy that girls need to persevere through a long day at school and for sports, music or other extracurricular activities (not to mention their social lives).

There’s a lot more to tell your daughter: Fats slow the absorption of carbohydrates and other parts of a meal into the blood, keeping her satiated, and curbing cravings.

Fats play an essential role in hormone development, which is fundamental during puberty — it can affect everything from lifelong fertility to mood stabilization and the ability to manage stress.

Furthermore, without fat as a catalyst, the body is unable to digest and absorb the fat-soluble vitamins A, D, E and K. Fat is needed to convert beta-carotene to Vitamin A.

And these vitamins are no joke: Vitamin A is essential for healthy skin, Vitamin D for immunity, Vitamin E is an antioxidant, and Vitamin K plays a role in blood clotting. Therefore, eating a colorful salad without nuts, seeds, avocado or oil is limiting the nutritional benefits of that salad.

Good fats are essential to brain development: The healthy brain is about 60 percent structural fat, and the most prevalent structural fat is DHA, one of the omega-3 fatty acides. (DHA is an essential part of healthy human breast milk too, which suggests that it is intended for babies to consume a lot of it during the first year, a time of unmatched brain growth .)

Finally, on a more superficial note, good fats build cell membranes that are essential for healthy hair and skin.

Let’s begin giving healthful fat the good name it deserves, so our girls start eating it. And before you conclude this chat with your daughter, explain that rising estrogen levels sometimes make girls crave sweets. Help her understand that this is normal, and there are alternatives to sugar that will make her feel energized rather than sluggish and moody. Moms, if only somebody had shared this news with us when we were teenage girls; we might have saved ourselves, and our own mothers, from a few really bad moods.