Weight‑Loss Tactics: A New Guideline on Keeping Muscle

Muscle Retention Depends on Protein and Timing

A recent position stand from the International Society of Sports Nutrition (ISSN) released a comprehensive review of popular dieting methods, including intermittent fasting, ketogenic diets, and high‑protein plans. The report, published in October 2026, evaluates how these approaches influence body fat, muscle mass, and long‑term health outcomes.

The ISSN panel examined data from 120 randomized trials involving over 5,000 participants. Their goal was to determine which strategies best preserve lean tissue while promoting fat loss. Findings suggest that while calorie restriction is essential, the composition of the diet and timing of meals play critical roles in maintaining muscle mass.

Are Low‑Carb Diets the Key to Fat Loss?

The study emphasizes that protein intake above 1.6 grams per kilogram of body weight per day is necessary for most adults engaged in weight loss. This threshold helps counteract the muscle‑breaking effects of caloric deficits. Additionally, the timing of protein consumption matters: spreading protein evenly across three to four meals each day supports muscle protein synthesis more effectively than large, infrequent doses.

Intermittent fasting protocols, such as the 16:8 method, can be compatible with muscle preservation if combined with adequate protein and resistance training. However, the ISSN cautions against prolonged fasts of 24 hours or more, which may increase muscle breakdown, especially in untrained individuals.

What Should I Do If I Want to Lose Weight and Keep Muscle?

The guideline questions the long‑standing belief that low‑carbohydrate diets automatically lead to superior fat loss. While ketogenic diets can produce rapid initial weight loss, the review notes that the majority of weight lost in the first six weeks is water weight. Over 12 months, the difference between low‑carb and balanced‑macronutrient diets narrows to less than 1.5 kilograms.

Moreover, the study highlights that carbohydrate restriction can impair high‑intensity training performance. Athletes who reduce carbs below 50 grams per day may experience decreased power output, making it harder to sustain a calorie deficit through exercise. Therefore, the ISSN recommends a moderate carbohydrate intake—especially around workouts—to maintain training intensity and protect muscle mass.

Frequently Asked Questions

The report offers practical guidance for individuals seeking to lose fat without sacrificing strength. First, set a moderate calorie deficit of 500 to 750 calories per day. Second, consume at least 1.6 grams of protein per kilogram of body weight daily, split into three to four meals. Third, incorporate resistance training at least three times per week, focusing on compound movements like squats and deadlifts. Finally, monitor body composition changes every four weeks to adjust calorie intake or training volume as needed.

The ISSN also stresses the importance of adequate sleep and stress management, as both factors influence hormonal balances that affect muscle maintenance and fat loss. A holistic approach—combining nutrition, exercise, and recovery—offers the best chance for sustainable, lean weight loss.