Keto vs. Low-Carb: What’s the Real Difference?
Reviewed by Dr. Eric Westman, MD, MHS: (September 2025)
For many American women navigating their 40s, 50s, and beyond, the quest for a sustainable and effective approach to health and wellness can feel like a full-time job. The body’s landscape changes during this time, bringing with it new challenges: a shifting metabolism, hormone fluctuations, and a tendency for weight to settle in ways it never did before. In the vast world of nutritional advice, two terms consistently rise to the top: low-carb and keto.
They are often used interchangeably, which can be confusing. Is one just a stricter version of the other? Are the benefits the same? Most importantly, which—if either—is the right choice for a middle-aged woman looking not just to lose weight, but to cultivate long-term vitality and health? This article will cut through the noise and provide a clear, in-depth comparison of the ketogenic and low-carb diets, specifically tailored to the unique needs and concerns of women in their middle years.
What is a Low-Carb Diet?
At its core, a low-carb diet is exactly what it sounds like: an eating plan that restricts carbohydrates, particularly from sugary and starchy foods, in favor of protein and healthy fats.
Think of it as a flexible framework rather than a rigid set of rules. While there’s no single, universally agreed-upon definition, a low-carb diet typically involves consuming between 50 to 130 grams of carbohydrates per day. This is a significant reduction from the standard American diet, which often exceeds 250 grams daily.
Foods to Eat:
- Animal proteins: beef, pork, lamb, poultry, game meats
- Fish and seafood: salmon, tuna, shrimp, other finfish and shellfish
- Eggs
- Non-starchy vegetables: spinach, broccoli, cauliflower, bell peppers, zucchini
- Lower-carb fruits: berries, avocados, tomatoes
- Nuts and seeds
- Healthy fats: butter, tallow, olive oil, avocado oil, coconut oil
- High-fat dairy: cheese, butter, Greek yogurt
Foods to Limit or Avoid:
- Sugar-sweetened beverages: soda, sweet tea, fruit juice, sugary coffee drinks
- Grains: bread, pasta, rice, cereal, oatmeal
- Beans & pulses
- Starchy vegetables: potatoes, corn, peas
- Most fruits (especially tropical ones like bananas and mangoes)
- Processed snacks: crackers, chips, cookies
(Note that the lists above are just some examples, not exhaustive lists.)
The primary goal of a low-carb diet is to lower blood sugar and insulin levels. Insulin is the hormone responsible for shuttling glucose (from carbs) into cells for energy. When carb intake is high, insulin levels are consistently elevated, which can signal the body to store excess energy as fat. By reducing carbs, you lower insulin, encouraging your body to burn stored fat for fuel instead. For a middle-aged woman, this approach can be particularly beneficial. As estrogen levels decline during perimenopause and menopause, insulin sensitivity can decrease, making it easier to gain weight, especially around the midsection. A low-carb diet directly counteracts this by helping to stabilize blood sugar and reduce the hormonal signals that promote fat storage.
What is the Ketogenic (Keto) Diet?
The ketogenic diet is a much stricter form of a low-carb diet. It’s not just about reducing carbs; it’s about restricting them to a very low amount in order to facilitate a metabolic state called ketosis.
On a keto diet, carbohydrate intake is typically limited to under 50 grams per day, and often as low as 20 grams. There are no specific macronutrients (“macros”) that need to be followed, but when carbs are limited to this extent, fat makes up the majority of calories on a keto diet, with protein second and carbs last. When the supply of glucose is very low, the body adapts by turning to fat as its main fuel source. The liver breaks down fat (fatty acids) into molecules called ketones, which can then be used for energy in addition to the fat being used.
Foods to Eat: The food list is similar to a low-carb diet, but with an even greater emphasis on keeping the carbs ultra-low. All the same proteins and fats are permitted. Non-starchy vegetables, nuts, and high-fat dairy products can be included in small amounts.
Foods to Strictly Avoid: The “limit” list from the low-carb diet becomes a hard “avoid” list on keto. No grains, no beans, no starchy vegetables, no sugary beverages. The non-starchy vegetables, nuts, and other carb-containing foods that are permitted more generously on a low-carb diet need to be strictly limited on keto. You can include them, but the total amount needs to be very low, because those carbs can add up quickly and prevent you from experiencing the most powerful effects of keto.
The ketogenic diet’s potential benefits can be compelling. Beyond weight loss, ketosis is associated with reduced inflammation, improved mental clarity (bye-bye, brain fog!), and steadier energy levels without the crashes that come from blood sugar spikes.
The Key Differences in Detail
The most crucial distinction between the two diets is the metabolic state of ketosis. A standard low-carb diet does not aim to produce a significant level of ketones, while the keto diet is defined by it. This core difference informs their varying rules and approaches.
The primary goal of a standard low-carb diet is to reduce insulin, encourage the body to burn stored fat, and improve blood sugar control. In contrast, the ketogenic diet’s specific objective is to achieve and maintain ketosis. This is reflected in the daily carbohydrate intake: a low-carb diet is more flexible, typically allowing for 50 to 130 grams of carbs per day, whereas the keto diet is much stricter, requiring an intake of under 50 grams (and often just 20-30 grams) to ensure ketosis is maintained.
A low-carb diet, with its wider range of food choices and higher carb limit, might be easier for some people to follow over the long term compared to a stricter keto approach. But sustainability is in the eye of the beholder: what feels restrictive to one person might feel liberating to someone else, particularly if the stricter approach is more powerful for them and yields them better results than the more flexible one. (If a diet frees you of migraines, joint pain, heartburn, brain fog, high blood sugar, and even improves your mental health – all of which keto diets are proven to do – you might love following it, rather than feeling restricted or resentful.)
Navigating Hormonal Changes: A Special Consideration
The transition through perimenopause and menopause is a time of profound hormonal change. This is where choosing the right dietary approach becomes especially nuanced for women.
- Insulin Resistance: As estrogen declines, the body can become less responsive to insulin. Both low-carb and keto diets excel at improving insulin sensitivity, which is a major advantage for preventing age-related weight gain and reducing the risk of type 2 diabetes.
- Bone Health: Menopause is often a period of accelerated bone loss. While some concerns have been raised about whether higher protein diets could affect bone health, current research suggests that adequate protein is actually crucial for maintaining bone density, especially when combined with resistance training. The key is ensuring a nutrient-dense diet rich in bone-supportive minerals, which is possible on both keto and low-carb plans with careful food choices.
Which Approach is Right for You?
The best diet is the one you can stick with that makes you feel your best. Here’s a way to think about the choice:
A ketogenic diet may be a good strategy for you if:
- You have significant weight to lose and want to kickstart the process.
- You struggle with severe sugar cravings and need clear boundaries.
- You have insulin resistance, pre-diabetes, or type 2 diabetes. (Get medical supervision before starting keto if you use insulin.)
- You are seeking potential cognitive or mental health benefits, like improved focus and clarity, more stable moods, or improvement in anxiety or depression.
A low-carb diet may be a better long-term lifestyle for you if:
- You do not have a medical condition that necessitates a strict keto diet.
- You want a more flexible approach to weight management.
- The idea of extreme restriction feels overwhelming or has led to failure in the past.
- You are very active and find you need a bit more carbohydrate to fuel your workouts.
Many people find success with a phased approach. They might use a strict ketogenic diet for an initial period (3-6 months) to become fat-adapted and break sugar addiction, then transition to a more moderate low-carb plan for long-term maintenance.
The Bottom Line
Both keto and low-carb diets can be effective for middle-aged women to reclaim health, lose weight, and experience increased overall vitality and wellbeing. The real difference between these dietary approaches isn’t so much in their food guidelines, but rather in their fundamental goals and mechanisms. The keto diet facilitates a specific metabolic state – ketosis – through strict carb restriction, offering rapid results but demanding rigid adherence. A low-carb diet provides a more flexible, forgiving path that focuses on reducing insulin and improving metabolic health, making it a more sustainable lifestyle for many.
Consult your healthcare provider before starting any new diet, especially during a time of significant hormonal change. They can help you assess your individual health needs, run baseline bloodwork, and ensure you embark on your journey safely. Ultimately, whether you choose keto, low-carb, or a hybrid of the two, the goal is the same: to find a way of eating that nourishes your body, sharpens your mind, and empowers you to live with health and vitality through midlife and beyond.
Reviewer Bio
Eric Westman, MD, MHS, is an Associate Professor of Medicine at Duke University, the Medical Director of Adapt Your Life Academy and the founder of the Duke Keto Medicine Clinic in Durham, North Carolina. He is board-certified in Internal Medicine and Obesity Medicine and has a master’s degree in clinical research. As a past President of the Obesity Medicine Association and a Fellow of the Obesity Society, Dr. Westman was named “Bariatrician of the Year” for his work in advancing the field of obesity medicine. He is a best-selling author of several books relating to ketogenic diets as well as co-author on over 100 peer-reviewed publications related to ketogenic diets, type 2 diabetes, obesity, smoking cessation, and more. He is an internationally recognized expert on the therapeutic use of dietary carbohydrate restriction and has helped thousands of people in his clinic and far beyond, by way of his famous “Page 4” food list.
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