Keto vs. Low-Carb for Perimenopause: What Actually Works for Weight Loss?

Why Weight Changes in Perimenopause Feel So Frustrating

You have not dramatically changed your eating habits, but the weight is shifting anyway. It is collecting around your abdomen in a way that feels unfamiliar. You eat the same things you always have and the results are different. You are not imagining this.

During perimenopause, declining estrogen levels shift where your body stores fat, increase insulin resistance, slow metabolic rate, and disrupt the hormones that regulate hunger and fullness. This is genuinely harder, and it requires a genuinely different approach. Keto and low-carb diets both address some of these mechanisms, but they do so with different degrees of restriction.

What Low-Carb Eating Means

Low-carb is a broad category. Most definitions consider an eating pattern low-carb when it reduces daily carbohydrate intake to roughly 50 to 150 grams per day, compared to the typical Western diet of 200 to 300 grams or more. Low-carb approaches reduce refined carbohydrates, sugars, and starchy foods while increasing protein and fat intake.

Low-carb eating addresses insulin resistance directly. By reducing the carbohydrate load, blood sugar spikes become less frequent and insulin levels stabilize. For women in perimenopause, where insulin sensitivity is already declining, this can be a meaningful lever for weight management and energy stability. Low-carb allows a wider range of foods including whole grains in smaller amounts, legumes, fruit, and starchy vegetables.

What Keto Eating Means

The ketogenic diet is a more restrictive form of low-carb eating, typically limiting carbohydrates to 20 to 50 grams per day. At this level of restriction, the body shifts from using glucose as its primary fuel source to burning fat and producing ketones. This metabolic state is called ketosis.

Keto is characterized by very high fat intake, moderate protein, and minimal carbohydrates. Foods like bread, pasta, rice, most fruits, legumes, and starchy vegetables are largely excluded. The approach requires more planning and a more significant shift in eating habits than a moderate low-carb approach.

What the Evidence Shows for Perimenopause

Research specifically in perimenopausal and menopausal women is limited, but the available evidence suggests both approaches can support weight loss and metabolic improvements. Low-carb diets have a more substantial evidence base overall, including in midlife women, for reducing fasting insulin, improving blood sugar regulation, reducing triglycerides, and supporting weight loss.

Keto has shown promise in some studies for rapid initial weight loss, reduced appetite through ketone effects on hunger hormones, and improved triglycerides. However, most keto studies are short-term and it is unclear whether the strict restriction is sustainable long enough to produce lasting results for the majority of people. Some research also suggests that very low-carb diets may affect thyroid function in some individuals, which is worth noting given the overlap between thyroid issues and perimenopause.

Muscle Mass: A Critical Consideration

During perimenopause, preserving muscle mass becomes more important than it was in earlier decades. Muscle is metabolically active tissue that supports your resting metabolic rate, your bone density, and your insulin sensitivity. Both keto and low-carb approaches can preserve or even improve muscle mass when protein intake is adequate, but this requires attention.

Very low-carb or keto diets without adequate protein can lead to muscle loss, particularly if overall calorie intake is too low. Pairing either approach with strength training is important for maintaining the muscle mass that supports long-term metabolic health. Protein targets in the range of 1.2 to 1.6 grams per kilogram of body weight are commonly cited in research on midlife women, though your specific needs depend on your health and activity level.

Practical Sustainability: Which You Can Actually Stick With

Keto requires eliminating most fruit, all grains, most legumes, and many vegetables. For social eating, travel, and family meals, this level of restriction can be genuinely challenging. Many women find they can sustain keto for a few weeks or months but struggle to maintain it as a permanent lifestyle. When keto is abandoned, rapid weight regain is common, partly because the initial loss includes water weight lost as glycogen stores deplete.

A moderate low-carb approach is more flexible. It allows for the occasional piece of fruit, a portion of rice, or a social meal without throwing off the entire pattern. This flexibility tends to make it more sustainable for the long term, which matters far more than the initial pace of weight loss.

Hormones, Sleep, and the Carb Connection

Some women in perimenopause find that extremely low-carb eating worsens their sleep or increases anxiety, possibly because carbohydrates support serotonin and melatonin production. If you try keto and notice disrupted sleep or increased irritability, this is worth paying attention to. A slightly more generous carbohydrate intake, timed in the evening, may help.

This is not universal. Some women feel significantly better on keto and find sleep improves alongside weight loss. Your personal response matters more than a general rule.

Tracking Your Patterns

Dietary changes during perimenopause can take several weeks to show clear effects on weight, energy, and symptoms. Tracking consistently helps you separate genuine signal from natural day-to-day fluctuation.

PeriPlan lets you log symptoms and check in daily so you can track patterns over time. If you are experimenting with a dietary change, logging your energy levels, sleep quality, and mood alongside your food choices helps you build a clearer picture of what is actually working for your body.

What to Prioritize Whatever Approach You Choose

Regardless of whether you go low-carb or keto, some nutritional priorities remain consistent for perimenopause: adequate protein to preserve muscle, enough fiber to support gut health and blood sugar stability, anti-inflammatory foods to support joint and hormonal health, and enough calories to avoid triggering a stress response that elevates cortisol and undermines your goals.

Any significant dietary change is worth discussing with your doctor or a registered dietitian, particularly if you have any underlying health conditions or take medication.

There Is No Perfect Diet, Only the Right One for You

Both keto and low-carb can support weight management and metabolic health in perimenopause. Neither is universally better. The right approach is the one you can sustain, that fits your food preferences, your social life, and your energy needs, and that makes you feel well rather than depleted.

You are not failing if a particular approach does not work for you. Keep adjusting, keep listening to your body, and seek professional guidance when you need it.

This content is for informational purposes only and does not replace medical advice. Always consult your healthcare provider about your specific situation.