Nutrition for Fat Loss

Fat loss comes down to a sustained caloric deficit (see Setting Calorie Targets for Fat Loss, Maintenance, and Gain), but how it's run determines whether you lose fat or fat plus muscle, and whether you can stick with it. Core principles:

• Moderate deficit: size it to lose ~0.5–1% of body weight per week (Helms et al. 2014); ~500 kcal/day is a common first guess (see Setting Calorie Targets for Fat Loss, Maintenance, and Gain, Safe Rate of Caloric Deficit and Weight Loss). Faster isn't better: in elite athletes who kept lifting, a 0.7%/week target (about a 19% cut in intake) added lean mass, while a 1.4%/week target (about a 30% cut) did not (Garthe et al. 2011). Leaner people should go slower (ISSN diets stand, 2017 edition). Very-low-energy (under 800 kcal/day) and low-energy (800–1,200 kcal/day) diets lose more weight short term but have no long-term advantage over less aggressive restriction, may cost more lean mass, and risk shortfalls in vitamins, minerals and fiber (ISSN 2026).
• High protein: the 2026 ISSN stand puts 1.2–1.6 g/kg of body weight a day as appropriate for most people losing weight, and 1.9–3.2 g/kg to maximize lean-mass retention in lean, resistance-trained people in a deficit (the 2017 edition said 2.3–3.1 g/kg of fat-free mass). Total daily protein comes first; for active people, spreading it across at least three protein-rich meals may help further. Protein also helps satiety (see Protein-Sparing in a Caloric Deficit).
• Resistance training: with enough protein, the ISSN calls it an indispensable protector of lean mass in a sustained deficit, whatever the diet type.
• Diet style is flexible: the carbohydrate–fat split can follow preference (keto through low-fat perform similarly for weight loss, though keto tends to lose more fat-free mass, partly glycogen and water), intermittent-fasting variants perform like continuous restriction, and meal frequency can suit you (ISSN 2026; see Low-Carbohydrate and Ketogenic Diets, Intermittent Fasting).
• Satiety and volume: build meals around fiber-rich, high-volume, low-energy-density foods (vegetables, fruit, legumes, lean protein — see Dietary Fiber and Gut Health) so you feel full on fewer calories.
• Sustainability: choose a pattern you can maintain (see The Best Diet Is the One You Adhere To); allow some flexibility to prevent rebound.

Practical tactics: track intake at least initially, keep liquid calories and added sugars low, manage hunger with protein/fiber/water, get adequate sleep (poor sleep raises hunger and risks muscle loss), and expect non-linear scale movement (water/glycogen and hormonal fluctuations) — judge progress over 2+ weeks. Learning to cook at home and planning meals ahead puts you in control, and support from health professionals and the people around you helps (ISSN 2026). When loss stalls, the stand treats the plateau as a cue to practise holding your progress; the slowdown in energy expenditure (adaptive thermogenesis) isn't inevitable and may fade once weight is stable. A structured fat-loss block is a "cut" (see Cutting (Fat-Loss Phase)).

• Moderate deficit sized to ~0.5–1% body weight/week (Helms 2014); ~0.7%/week kept and even added lean mass in athletes (Garthe 2011).
• Protein: 1.2–1.6 g/kg body weight for most people; 1.9–3.2 g/kg for lean, trained lifters in a deficit (ISSN 2026; 2017 edition: 2.3–3.1 g/kg of fat-free mass); ≥3 protein-rich meals.
• Resistance training plus enough protein are indispensable to retain lean mass.
• Keto to low-fat and intermittent fasting vs continuous restriction perform similarly; pick by preference (ISSN 2026).
• VLED/LED (<800 / 800–1,200 kcal/day): short-term only.
• Emphasize fiber-rich, high-volume, low-energy-density foods.
• Sustainability and sleep matter; judge progress over 2+ weeks.