Health & Wellness

The Menopausal Brain Has a New Fuel Preference—’The Art of Being Well’ Explains the Fog

December 16, 2025

If brain fog, low energy, or sudden mental fatigue showed up in midlife without warning, this episode of The Art of Being Well offers a missing piece of the puzzle. Dr. Will Cole sits down with Dr. Mindy Pelz to explain why the menopausal brain processes fuel differently—and why eating the same way you did in your 20s can suddenly stop working.

Pelz breaks down how estrogen decline changes the brain’s relationship with glucose, making it harder to access steady mental energy. The result is focus crashes, mood dips, and that familiar fog that no amount of caffeine seems to fix. And the solution isn’t extreme dieting or constant tracking. Instead, Pelz points to ketones as the preferred fuel source for the postmenopausal brain—and shows how fasting windows, not carb obsession, help women regain clarity without burning out their nervous systems.

Why the menopausal brain becomes less sensitive to glucose

The brain’s relationship with fuel changes as estrogen declines. For decades, glucose has been the brain’s go-to energy source, but during menopause, that system becomes less efficient. As Pelz explains, “a woman’s brain becomes less sensitive to glucose,” which helps explain why meals that once felt energizing can suddenly lead to crashes or brain fog.

Estrogen plays a key role in how the brain transports and uses glucose. When levels drop, the brain struggles to access that fuel as easily, even if blood sugar is technically available. The brain is asking for a different kind of support, but most women are still feeding it the same way they did in their 20s and 30s. That disconnect shows up as slower word recall, reduced focus, and that familiar feeling of running on empty despite eating “normally.”

Ketones become the brain’s preferred fuel source

As glucose becomes harder for the menopausal brain to access, Pelz says ketones step in as a more reliable energy source. Ketones don’t require the same insulin signaling or estrogen-supported pathways to reach brain cells, which makes them easier to use during this hormonal transition. The payoff is steadier energy and clearer thinking overall.

“Everything I can see shows that a postmenopausal brain likes ketones a lot more than it likes glucose,” Pelz says. Ketones provide a cleaner-burning fuel that supports mitochondrial health and helps calm neuroinflammation, both of which matter more as the brain rewires in midlife.

Fasting windows work better than carb restriction

Pelz is careful to separate metabolic support from diet extremism. While ketogenic diets can have benefits, she doesn’t see long-term carb restriction as necessary—or sustainable—for most women in midlife. Instead, she prefers time-restricted eating because it allows the body to access ketones without forcing constant deprivation.

Fasting windows create a natural metabolic shift. By extending the time between dinner and breakfast to 15 to 17 hours, the body moves into ketone production on its own, without eliminating entire food groups. Pelz describes this as a gentler way to meet the brain’s new fuel needs while preserving flexibility and hormonal balance.

Carb restriction, on the other hand, can increase stress, elevate cortisol, and push women into an “all-or-nothing” mindset. Pelz sees that as counterproductive during a phase when the nervous system is already recalibrating. Fasting windows support clarity without overstimulation, structure without rigidity, and consistency without burnout—which is exactly what the menopausal brain responds to best.

Why exogenous ketones aren’t the answer

With ketones having such clear benefits for the menopausal brain, it’s tempting to look for a shortcut. Pelz cautions against that. While exogenous ketones can raise ketone levels quickly, she’s concerned about putting the body into what she sees as an unnatural metabolic state—especially when ketones are layered on top of high blood sugar.

Pairing exogenous ketones with a typical high-glucose diet can send mixed signals to the body, forcing it to process two competing fuel sources at once. Pelz argues that the brain benefits most when ketones are produced endogenously, through fasting and metabolic flexibility, not poured in from the outside.

She does leave room for strategic use. If exogenous ketones are used, Pelz suggests they belong in a fasted state, where they support an existing metabolic process instead of overriding it. The body already knows how to make what it needs. The goal is to create the conditions that allow it to do that—not to outsource the work to another supplement.

Eating for clarity, not control

After decades of dieting, tracking, and optimization, many women enter midlife exhausted by food decisions. Pelz’s approach moves in the opposite direction: simplify, nourish, and stop micromanaging signals your body already knows how to send.

Instead of counting macros, she emphasizes real food and rhythm. Utilize those fasting windows to support ketone production. Eat whole foods that stabilize blood sugar and support neurotransmitter function. And obsessive tracking can keep the nervous system in a state of low-grade stress—exactly what the menopausal brain doesn’t need. Eating for clarity means choosing foods that feel stabilizing, noticing how your energy responds, and trusting your body to guide adjustments over time.

To hear the full conversation on the menopausal brain, listen to The Art of Being Well wherever you get your podcasts.

** Remember, it’s always important to consult with your doctor before introducing any new diet changes or restrictions.