Why am I always hungry?

Sounds like you're burning more calories than you're taking in, if you've noticed an influx of hunger from switching to a more vigorous routine. I used to train pretty hard years ago and came across this problem before. I'd personally suggest adding more carbs to your diet to make up for the new deficit along with observing your body's response. Always remember - if you adjust your training, you will probably need to adjust your eating habits accordingly.

There are a lot of factors that contribute to hunger.

The most simple is your body reacting to changes in nutrition. A new program or not eating enough can cause your brain to release hormones to cause you to eat. It depends on how big your deficit is. It doesn't know you're working on your abs and thinks it's preventing your from starving to death.

For example normal workouts burn about 600 calories, but sometimes I bike some trails near my house. That burns about 1400 calories. If I don't eat at least an extra 500 calories of fat or sugar and drink lots of water all I can do for the rest of the day is sleep and eat pizza.

Also lack of sleep will cause it as well. When you sleep has an influence on when you're body wants to eat. So lack of sleep or frequent changes in your sleeping patterns will cause it.

Do you crave the same foods or types of food? I hear that might be a clue. Personally, it's been true for me in the past. When I'm lifting and not eating enough protein I crave meats. When I'm not eating enough general calories I crave fats and salts. I'm not really big on sugar so I almost never get that urge.

It's also easy to mistake thirst for hunger so if you're dehydrated it will cause you to want to eat.

This is quite common when you start working out. Also have you recently begun eating earlier? Eating breakfast for me helps me want to eat more throughout the day. Since your goal is gaining weight, I would just keep eating healthy things. If you get a little fat, it will help with the bulk.

Make sure you are consuming 100 to 120 grams of protein a day.

Protein is the key to weight loss and muscle build up. You should also consume high protein within 30 minutes of working out. Use MFP to monitor you protein. 3 ounces of chicken is 20 grams. You have to eat a lot to get the 100 to 120 grams of protein a day.

Are you using TDEE? If so, run your numbers again with the new exercise days added plus your new weight if you've gained/lost.

I am using TDEE, below is my training plan. How many times of training per week should I consider with this training plan to calculate my TDEE?

Monday: Workout A on machines: Arm Curl (6x8), Lat pull (6x8), Dips (6x8), Lying Triceps (6x8), Shoulder press (6x8), Chin up (6x8), Cardio (20 minutes running)

Tuesday: moderate cardio (cycling 26 miles)

Wednesday: Free weights work out: Arm Curl (6x8), Tricep Extensions (6x8), Bench press (6x8), Crunch (6x30), Shoulder press (6x8), Lying Fly (6x8), Supine bicep curl (6x8), Squat (6x8)

Thursday: moderate cardio (cycling 26 miles)

Friday: Workout B on machines: Leg press (6x8), Leg Curls (6x8), Chest press (6x8), Chest fly (6x8), Arm Curl (6x8), Leg raise (6x8), Cardio (20 minutes running).

Saturday: rest day

Sunday: Workout A

And the following week I switch workout A with workout B. I am trying to do each set at my maximum (sometimes I only manage to do 3 reps).

I'd consider that 6 days per week or the highest activity level.

Are you using TDEE? If so, run your numbers again with the new exercise days added plus your new weight if you've gained/lost.

I am using TDEE, below is my training plan. How many times of training per week should I consider with this training plan to calculate my TDEE?

Monday: Workout A on machines: Arm Curl (6x8), Lat pull (6x8), Dips (6x8), Lying Triceps (6x8), Shoulder press (6x8), Chin up (6x8), Cardio (20 minutes running)

Tuesday: moderate cardio (cycling 26 miles)

Wednesday: Free weights work out: Arm Curl (6x8), Tricep Extensions (6x8), Bench press (6x8), Crunch (6x30), Shoulder press (6x8), Lying Fly (6x8), Supine bicep curl (6x8), Squat (6x8)

Thursday: moderate cardio (cycling 26 miles)

Friday: Workout B on machines: Leg press (6x8), Leg Curls (6x8), Chest press (6x8), Chest fly (6x8), Arm Curl (6x8), Leg raise (6x8), Cardio (20 minutes running).

Saturday: rest day

Sunday: Workout A

And the following week I switch workout A with workout B. I am trying to do each set at my maximum (sometimes I only manage to do 3 reps).

I'd consider that 6 days per week or the highest activity level.

Really? I really underestimated my TDEE... Based on http://iifym.com/tdee-calculator/, my TDEE is 2841 kcal. Does it mean I can eat more ?

Probably-- especially if you're trying to gain weight.

Keep in mind that your logging has to be accurate and the TDEE calculator is an estimate and adjust according to your actual results.

Also keep in mind if you bump up your calories you may gain temporary water weight at first.

Same thing happened to me when I switched from moderate lifting to heavy lifting. The first two weeks or so I felt like I couldn't keep up with my appetite.

Are you using TDEE? If so, run your numbers again with the new exercise days added plus your new weight if you've gained/lost.

I am using TDEE, below is my training plan. How many times of training per week should I consider with this training plan to calculate my TDEE?

Monday: Workout A on machines: Arm Curl (6x8), Lat pull (6x8), Dips (6x8), Lying Triceps (6x8), Shoulder press (6x8), Chin up (6x8), Cardio (20 minutes running)

Tuesday: moderate cardio (cycling 26 miles)

Wednesday: Free weights work out: Arm Curl (6x8), Tricep Extensions (6x8), Bench press (6x8), Crunch (6x30), Shoulder press (6x8), Lying Fly (6x8), Supine bicep curl (6x8), Squat (6x8)

Thursday: moderate cardio (cycling 26 miles)

Friday: Workout B on machines: Leg press (6x8), Leg Curls (6x8), Chest press (6x8), Chest fly (6x8), Arm Curl (6x8), Leg raise (6x8), Cardio (20 minutes running).

Saturday: rest day

Sunday: Workout A

And the following week I switch workout A with workout B. I am trying to do each set at my maximum (sometimes I only manage to do 3 reps).

I'd consider that 6 days per week or the highest activity level.

Really? I really underestimated my TDEE... Based on http://iifym.com/tdee-calculator/, my TDEE is 2841 kcal. Does it mean I can eat more ?

Probably-- especially if you're trying to gain weight.

Keep in mind that your logging has to be accurate and the TDEE calculator is an estimate and adjust according to your actual results.

Also keep in mind if you bump up your calories you may gain temporary water weight at first.

OK thanks for your advice. I noticed after a night out, the scale goes up (up to 3kgs some days) it's probably water weight.

Yes, exactly like that.

When I was lifting I used to have a can of Tuna after my session, really filling and full of protein, as peolpe have said you may need more carbs to fuel your workouts and your body is telling you this?.

I also used to eat a lot of chopped apple with cottage cheese for mid morning snacks when training.

You probably aren't eating enough. 2600 is probably not much more than your BMR if you aren't aiming for fat loss. Be careful with the beer (no real nutritional value) and the peanut butter (good protein but lots of fat also). Be careful that you don't overtrain. Your reps are unusual - most body builders stick with 3 sets of 10 - 15 reps. if you aim for failure every time you will overtrain and all things will come to a screeching halt.

Try eating 5-6 times a day with a ratio of 50% carbs, 30% protein and 20% fat. aim for 500 calorie meals. after a few weeks adjust your intake/ratios.