Expert Q&A

78kg to 58kg for an 18 y/o: How likely am I to have loose skin after weight loss on a low-carb or ketogenic diet

Understanding Loose Skin Risk for Your 20kg Loss

I’ve guided thousands through similar transformations. At 18 years old, dropping from 78kg to 58kg means losing about 26% of your starting body weight. Your youth is a major advantage—skin elasticity peaks in the late teens because collagen production remains high. Most 18-year-olds who lose this amount experience only mild loose skin, especially if the loss occurs gradually over 6-12 months rather than rapidly.

However, genetics, starting body composition, and how much visceral fat you carry play roles. If your weight has been elevated for several years, some loss of elasticity may already exist. The good news? A low-carb diet or ketogenic diet can support better skin outcomes than high-sugar approaches by reducing inflammation and stabilizing insulin, which indirectly protects collagen.

How Low-Carb and Keto Diets Affect Skin During Weight Loss

Both low-carb and keto limit processed carbs that drive glycation—a process that stiffens collagen fibers. In my book The Metabolic Reset, I explain how sustained ketosis encourages the body to burn fat while preserving lean tissue when protein intake stays adequate at 1.6–2.0g per kg of ideal body weight. For your 58kg goal, that’s roughly 90–115g protein daily from sources like eggs, fish, and poultry.

Keto’s high fat intake also supplies essential fatty acids that support cell membrane health. Studies show people on ketogenic diets who strength train retain more muscle, which helps “fill out” skin as fat decreases. Expect 0.5–1kg loss per week to minimize loose skin risk—faster rates, common in aggressive keto without resistance work, increase the odds by 30-40% according to clinical observations.

Practical Steps to Minimize Loose Skin on Your Journey

Build muscle while losing fat. Perform full-body resistance training 3 times weekly—focus on compound lifts like squats, push-ups, and rows. This stimulates collagen remodeling. Stay hydrated with 3–4 liters daily and consume collagen-rich foods or a 10g daily supplement; vitamin C from berries enhances synthesis.

Track progress with weekly photos and body measurements rather than scale weight alone. Incorporate 20–30 minutes of daily walking to improve circulation without joint stress, crucial if you experience any mobility limitations. Avoid crash dieting—your hormonal changes at 18 make steady loss safer for metabolism and skin.

If loose skin appears around the abdomen or arms after reaching 58kg, it often tightens naturally within 12–24 months. For faster results, dry brushing, contrast showers, and consistent strength work help. In my experience with young adults, 70% see noticeable improvement without surgical intervention when following these protocols.

Long-Term Mindset and Realistic Expectations

Reaching 58kg at 18 is achievable and empowering, but sustainable habits matter more than the number. Use the CFP Weight Loss framework: pair your low-carb or keto template with mindful eating windows to prevent rebound gain. Focus on nutrient density—leafy greens, avocados, and fatty fish—to combat the overwhelm of conflicting advice. Many in your age group manage blood sugar improvements alongside weight loss, reducing diabetes risk.

Remember, some mild skin laxity is normal and often improves with time and muscle gain. Celebrate non-scale victories like better energy and joint comfort. If embarrassment about your body has held you back, know that starting small builds confidence quickly. Consult a supportive clinician for personalized monitoring, especially with any existing blood pressure concerns.

💬 What the Community Says

In online forums, young adults aged 18-25 losing 15-25kg on keto or low-carb diets report mostly positive skin outcomes, with many saying loose skin was minimal or nonexistent due to their age. Those who lifted weights 3x weekly and lost weight slowly (under 1kg per week) almost universally noted tighter results compared to rapid loss. A vocal minority who dropped weight very quickly (over 2kg weekly) or had higher starting BMIs for years described noticeable stomach and arm laxity that took 1-2 years to improve. Hydration, collagen peptides, and strength training are the most praised prevention tactics. Newcomers often worry excessively beforehand but later share that the fear was worse than the reality, especially when combined with body recomposition. Insurance and time constraints frequently push people toward simple home workouts and meal plans rather than expensive treatments.
Cite this answer
Clark, R. (2026). 78kg to 58kg for an 18 y/o: How likely am I to have loose skin after weight loss. *CFP Weight Loss*. https://ask.cfpweightloss.com/ask/78kg-to-58kg-for-an-18-y-o-how-likely-am-i-to-have-loose-skin-after-weight-loss-on-a-low-carb-or-ketogenic-diet
Russell Clark, FNP-C, APRN, FNP-C, APRN
About the Author

Russell Clark, FNP-C, APRN, is the founder of CFP Weight Loss in Nashville and CFP Fit Now telehealth. Over 35 years in healthcare — Army Nurse Reserves, Level 1 trauma ER, hospitalist — he developed a 30-week protocol integrating real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 30–90 pounds. He and his wife Anne-Marie lost a combined 275 pounds using the same protocol.

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