Beyond Calories In, Calories Out: The Deeper Truth About Weight Loss After 40

For years, the simple advice to “eat less and move more” dominated conversations about weight loss. While this concept—known as "calories in, calories out" (CICO)—is scientifically accurate at its core, it oversimplifies the complex biological and lifestyle factors that influence weight loss, especially for women over 40.

As women transition into perimenopause and menopause, hormonal changes, metabolic adaptations, and lifestyle demands make it harder to achieve results with CICO alone. If you’re struggling to lose weight, the issue lies in one of two areas: either your “energy in” (calories consumed) is too high, or your “energy out” (calories burned) is too low. However, addressing this imbalance requires a deeper understanding of how your body works.

In this article, we’ll break down the nuances of CICO, explore how hormones, thyroid health, and lifestyle factors play a role, and provide practical strategies to help you reach your goals.

The Basics of Calories In, Calories Out (CICO)

At its simplest, weight loss occurs when you consume fewer calories than your body burns. Here's how the CICO equation works:

Calories In:

This includes all the calories you consume from food and beverages.

Calories Out:

This represents the calories your body burns through basal metabolic rate (BMR), physical activity, digestion, and other processes.

While the equation is straightforward, applying it to real life is far more complicated. Tracking calories accurately can be difficult due to factors like food label inaccuracies, portion size estimations, and individual metabolic variations. Even more, hormonal and lifestyle changes can significantly affect how your body processes and uses energy.

Why Hormones and Metabolism Matter After 40

As women age, their bodies undergo hormonal and metabolic changes that make it harder to maintain or lose weight. Let’s dive into the key factors at play.

Hormonal Shifts After 40

Perimenopause and menopause bring fluctuations in estrogen and progesterone, which can:

• Increase fat storage, particularly around the midsection.
• Disrupt hunger and satiety signals due to changes in ghrelin (hunger hormone) and leptin (fullness hormone).
• Contribute to insulin resistance, making it harder to manage blood sugar and energy levels.

Metabolic Adaptations

Lean muscle mass naturally declines with age, reducing your basal metabolic rate (BMR)—the number of calories your body burns at rest. This means you’ll burn fewer calories daily, even if your activity level remains the same. But thankfully, there are ways that prove to combat this and we'll go through options.

Thyroid Health and Weight Loss

The thyroid gland plays a critical role in regulating metabolism. If thyroid function is impaired (e.g., hypothyroidism), it can slow your metabolism and make weight loss more challenging. Extended low-calorie diets have been linked to thyroid dysfunction so it's important to learn how your body works and how much nutrients it needs. Symptoms of thyroid dysfunction include fatigue, weight gain, and cold intolerance.

How to Support Thyroid Health: Ensure adequate intake of iodine, selenium, and zinc through foods like seafood, eggs, and nuts. Avoid severe calorie restriction, which can suppress thyroid function.

Supporting “Calories Out”

Increasing “calories out” involves more than just adding exercise. Optimizing your body’s ability to burn energy requires attention to several key factors:

1. Improve Your Sleep

Poor sleep disrupts your body’s hormonal balance, increasing hunger hormones (ghrelin) and reducing satiety hormones (leptin). Lack of sleep also decreases energy levels, making it harder to stay active.

Tips for Better Sleep:

• Stick to a consistent bedtime and wake-up schedule.
• Limit caffeine and screen time in the evening.
• Create a relaxing bedtime routine, such as stretching or reading.

2. Manage Stress

Chronic stress elevates cortisol levels, which can lead to increased fat storage (especially around the belly) and cravings for high-calorie foods.

Stress-Reduction Strategies:

• Practice mindfulness or meditation for 10 minutes daily.
• Take regular breaks during your day to reset and recharge.
• Engage in restorative activities like yoga, walking, or journaling.

3. Address Nutritional Deficiencies

Low levels of iron, magnesium, vitamin D, and B12 can lead to fatigue and reduced calorie burn.

How to Correct Deficiencies:

• Include nutrient-rich foods like leafy greens, lean protein, nuts, and fatty fish in your diet.
• Consider supplementation if needed, under the guidance of a healthcare professional.

4. Avoid Low Energy Availability (LEA)

Low energy availability occurs when you’re not eating enough to fuel your body’s needs, leading to fatigue, reduced muscle recovery, and impaired metabolism.

LEA can lead to suppressed levels of thyroid hormones, such as T3 and T4, which are crucial for regulating metabolic rate. This suppression results in a slowed metabolism as the body conserves energy.

Tips to Fuel Workouts Effectively:

• Eat a small balanced meal with protein and possibly carbs if doing extensive cardio before exercise.
• Follow workouts with a nutrient-rich protein rich meal to support muscle recovery and growth.

Learn more about how personalized strategies can help you achieve sustainable weight loss here.

Supporting “Calories In”

Reducing calorie intake doesn’t mean extreme restriction. Instead, focus on improving the quality of the calories you consume. Read more about why fad diets don't work here.

1. Focus on Nutrient-Dense Foods

Choose foods that provide maximum nutrition for the calories they contain. Prioritize lean proteins, fiber-rich vegetables, whole grains, and healthy fats. A study from Obesity Silver Spring showed that for every 10g increase in soluble fiber, there was a 3.7% decrease in belly fat. One more tick mark to add to why fiber matters right along with muscle building protein.

2. Regulate Hunger and Cravings

High-fiber foods and balanced meals with protein, fat, and carbs help keep you fuller longer and stabilize blood sugar levels.

In fact several studies show that people who consume the highest amount of protein are least likely to have excess belly fat, which is a little tip we all need to know about. In addition, research shows that excess protein increases lean mass and not fat. Although weight gain can occur with excess protein, the majority of the weight was attributed to increased lean muscle, not fat storage particularly in individuals who resistance trained.

3. Practice Mindful Eating

Pay attention to hunger and fullness cues to avoid overeating. Slow down during meals and minimize distractions, such as watching TV or scrolling on your phone.

Practical Strategies for Balancing CICO

Ultimately to achieve weight loss, you need to create a calorie deficit by adjusting “energy in” or increasing “energy out.” Here’s how to do so sustainably with our bodies complexities in mind:

Small Adjustments to “Energy In”

• Start by tracking meals to identify patterns in your diet.
• Replace calorie-dense processed foods with nutrient-dense alternatives.
• Focus on portion control rather than extreme restriction. 

Boost “Energy Out” with Daily Movement

• Incorporate resistance training to build and maintain muscle, which increases metabolism.
• Increase Non-Exercise Activity Thermogenesis (NEAT), such as walking more, standing while working, or gardening.
• Aim for consistency and intensity—small daily efforts add up over time. Specifically for women as we age -intensity matters, so lift heavy!

Common Myths About CICO

Myth 1: "A Calorie is a Calorie."

Not all calories are equal. Nutrient-dense foods like lean protein and vegetables support satiety, metabolism, and overall health better than processed snacks.

Myth 2: "Exercise Alone is Enough to Lose Weight."

Exercise contributes to calorie burn but isn’t a standalone solution. Without managing calorie intake, creating a sufficient deficit is unlikely.

Myth 3: "CICO Doesn’t Work for Me."

CICO always applies, but factors like stress, sleep, and hormones can make achieving a calorie deficit more complex.

Conclusion

Weight loss boils down to balancing “calories in” and “calories out,” but achieving that balance is influenced by sleep, stress, hormones, and individual lifestyle factors. Tracking calories can provide a starting point, but it’s not essential—small, sustainable changes to your habits can create lasting results.

Approach your journey with curiosity and patience, knowing that everybody is different. By focusing on quality nutrition, regular movement, and holistic health, you can create the shift you desire and build a healthier, more energized life. 

What small, sustainable change will you start today to create the shift you want in your health and energy?