Bonnie J. Brehm, Randy J. Seeley, Stephen R. Daniels, and David A. D’Alessio, “A Randomized Trial Comparing a Very Low Carbohydrate Diet and a Calorie-Restricted Low Fat Diet on Body Weight and Cardiovascular Risk Factors in Healthy Women,” The Journal of Clinical Endocrinology & Metabolism: Vol 88, No 4; January 14, 2009. http://press.endocrine.org/doi/full/10.1210/jc.2002-021480.
60 year old and just started IF a week ago. I eat from noon to 8pm. The noon start works for me because I’m not starting my day with the thought of food! I LOVE FOOD AND LOVE TO EAT! I am moving away from some bad habits and it doesn’t seem that difficult for me with IF! Just one week in and I do feel better. Can’t wait till I’ve got a month under my belt.
The trick here is not only to avoid all obvious sources of carbohydrate (sweets, bread, spaghetti, rice, potatoes), but also to be careful with your protein intake. If you eat large amounts of meat, eggs and the like, the excess protein will be converted into glucose in your body. Large amounts of protein can also raise your insulin levels somewhat. This compromises optimal ketosis.
More good news: Snacks are totally allowed (and I'm not just talking about carrot sticks). There are plenty of packaged options out there designed for keto fans. FATBAR is one of them. These snack bars have 200 calories, 16 grams of fat, and four grams of net carbs. They're also plant-based and are made with almond or cashew butter, cocoa butter, coconut, pea protein, sunflower seeds, and chia seeds.
If you want to lose weight, consider starting by avoiding sugar and starch (like bread, pasta and potatoes). This is an old idea: for 150 years or more there have been a huge number of weight-loss diets based on eating fewer carbs. What’s new is that dozens of modern scientific studies have proven that, yes, on average low carb can be the most effective way to lose weight.